In March of 2013 Simpsons provided a new line of synthetic brushes for testing. The brushes went to members of two different forums. Unfortunately these brushes had issues from the start. In the U.S. the testing team found many problems with the new synthetic knots including cut tips and other anomalies that would not pass muster. On 16 April 2013 a post was made stating that a planned pass around was cancelled on the U.S. based shaving forum from Mark Watterson. Gentlemen, Sadly the Simpson synthetic pass around has been temporarily suspended. I highly value the opinion of the three original testers - Their comments have led me to believe that the product (synthetic fibre) is of a lesser standard to that of the competition on the market. That is not an acceptable outcome for me and the exact reason why these prototypes were manufactured. I have made the decision to recall the brushes. We will sit down with our fibre supplier in an effort to improve the quality of the material & offer a brush more be-fitting of the Simpson name. Synthetic material is not in the Simpson DNA, as you all know we are the world leaders in badger brush production. Back to the drawing board ... Apologies that the initial excitement has to be stifled but if we launch a new brush in full production runs it has to be 110% right. Mark On 24 April 2013 a post was made from a member of the U.K. based shaving forum stating. I have some bad news chaps, after my first shave with the brush it has a cavity... With that, the U.K. pass around test came to an end as well. So four brushes were complete failures, and with them plans for a Simpsons synthetic shaving brush seemed to go dim. Other companies would release synthetic brushes and it looked as if Simpsons would be sidelined from this market. If this were the end of the story it would not be a happy one for those looking to Simpsons for a high quality synthetic shaving brush, however, that was not the end of the story. Mr. Watterson and his team went back to the drawing board, and worked with a major fiber company to bring in a true Generation 4 fiber, and in the process developed a brand new knot. The prototype is the one you have seen in the following thread. http://theshaveden.com/forums/threa...1st-century-first-of-a-two-part-review.35363/ Now let me tell you about this new knot which is the heart of the matter. It is a true Generation 4 knot and is state of the art. It holds up well to pushing, circular motions, and after 4 days it has not failed to amaze me. In no way does this even resemble the original set of Simpsons synthetics that were in play earlier this year. It felt different, more substantial and soft, soft, soft at the tips. So lets get on to the testing. I had planned a series of 4 tests before writing a review to cover the major methods of lathering. The first test would be a true face lathering situation in which the brush would be paired with my favorite shave stick. Here are my notes on that shave. The Simpson Synthetic Badger is absolutely excellent in face lathering. Only one layer of stick on face yielded enough lather for 2 face passes 1 head pass and there was enough left over for another face and head pass if I desired. I did not have to go back and get more product, the brush held more than enough. The knot splayed very well and quickly generated lather and expelled it from the inside when pressed easily. The lather was extremely thick and uniform. The handle was easy to grip and extremely maneuverable. The 28 mm synthetic knot behaves size wise more like 24 mm badger brushes in my arsenal and is very reminiscent of them in action. On this very first test I prefer it over any equivalent Gen 4 brushes in face lathering. So now I waited for the next day and the next test. The next test would be bowl lathering with a well known cream. I was more concerned with testing the brush so I stuck with a cream that is very familiar to me. The Simpson Synthetic Badger is stunningly efficient in bowl lathering. As if it were tuned to face lathering from the prior test, it was equal to the tuning in the bowl. A dime size of product was able to produce enough lather for 2 face passes and 2 head passes with leftover. The placement and construction of this loft feels more like naturals than the other equivalent Generation 4 brushes. The knot has a slight give at the base which enhances the splay. All I can say at this point is that this is a very balanced brush. It does not act like a synthetic 28 mm but more like a natural 24 mm brush. With two differing test yield fantastic results, I would have to again wait for the next day and the next test. For test number three I moved back to face lathering with a glycerin based soap. Mama Bear's Dragon's Blood was used for this test. I love the scent and I wanted to see just how much lather could be produced with a limited amount of product. I simply let the brush take a swirl of soap (about 10 seconds) out of the tub and sealed the tub. It picked up soap easily and efficiently. Again it is simply excellent in face lathering One swirl on the brush yielded enough lather for 3 face passes 2 head passes, yes I did shave that much, and enough left over for another face pass if I desired. I had enough lather for two people to shave. The splay of the knot is fantastic. It really spreads out more like a Silvertip badger in terms of how the knot applies lather to the skin. This could be a soap destroyer if it were a natural, but the synthetic fibers will not be betrayed and it is very miserly in product use. Call it Simpsons Hyper Efficient Synthetic Badger, because that is what it is. For the last test I used the simple VDH Deluxe hard soap. Again, I am familiar with this soap with both natural and synthetics so it was a good choice to see if the brush would do a good job in picking up a hard soap. I let the brush a swirl of soap (about 10 seconds) and with a small amount of warm water in the bowl generated enough lather for 2 face passes and 2 head passes. The splay of the knot works better than any other synthetic I have used. This is a remarkably efficient, effective, and luxurious brush. The knot has every bit the feel of Generation 4 synthetics at the tips and the denser knot does not take away from the flow through or the softness at the tips. The backbone is moderately stiff so it feels more like a really fine Silvertip badger than other synthetics. This is an excellent brush, no doubt about it. So here is the long and the short of it. This brush to me outperforms ANY synthetic brush I have ever used, and by the way I have used a lot of them. The knot is better constructed, internally with a slight give (wiggle) at, or below, the breach which provides great splay. The knot is better constructed visually. This looks like a real solid bulb. The density provides a wonderful cushion without sacrificing flow through. The handle is solid Simpsons Chubby design and is well known for high quality and ease of grip. The brush is easy to maneuver for face lathering and is very effective in placing lather against the skin and feels more like a natural badger than any other synthetic I have used. This is one brush in which I will be sad to see leave the house Monday morning to go to the next tester in line. Now here is a statement directly issued to Mark Watterson and the team at Simpsons brushes. This is a prototype, but if production units are of as high a quality as this brush is, and the production units maintain a long level of reliable usage, then you and your team will have succeeded in making the very best synthetic brush on the market today. Then that brush will be remembered as a Simpsons Brush for the 21st Century. Edit: Given the fact that the loft was radically changed and the pricing scheme was changed when production units were issued as of March 2014 some of the information in this and the earlier review is no longer valid. Since this review the brush was released in production with significantly reduced lofts. The configuration I tested was 54 mm. Lofts for any synthetic brush with 5 to 6 mm adjustments (especially if reduced) will provide significantly different performance characteristics.