I decided to do a little shave-off with Gillette Rubies and Astra SP's just to see if I can legitimately tell the difference between them. I'm planning to use a variety of razors here just to get an idea if there are any that favor one blade or the other. I'll start here with the first couple blades of each and try to update it as my little test progresses. I'll keep the soap the same at least through each pair of blades to eliminate that variable as much as I can. Rubie #1 - I used a Pearl Flexi set on 2.5 which is usually a good setting for me. The first shave was very close but there was some alum feedback at the end, so I turned it down to 2 for the next two shaves. About as close but more comfortable. Pretty good shaves. Astra #1 - Flexi on 2 again. First shave was a little disappointing. There were some random whiskers left behind here and there and there was more alum feedback than with the Rubie. I decided this combo wasn't promising and switched the blade to a NEW Long Comb. The next two shaves were better but still I noticed the blade was missing some whiskers here and there. Not sure if this is because it's less sharp? I don't feel any tugging with the Astra but it seems to leave a little behind. There was less alum feedback with the NEW but there was still a little. Winner after 1 blade each - Rubie. The shaves were a little closer. Also, the blade felt smoother during the shave and that was confirmed by the alum afterward Astra #2 - NEW Short Comb - Like the last blade, I noticed some stray whiskers that needed touch-ups and there was some alum feedback after the first shave. The second shave was pretty good, like the blade had smoothed out. The third shave, that little bit of roughness was back so seemed like a good time to toss this blade. Rubie #2 - Also with NEW Short Comb - The shaves were pretty sublime. The blade cuts efficiently, leaving nothing behind and my skin had no signs of irritation afterward until the 3rd shave when there was just a hint of alum tingle. Winner after 2 blades - Rubie. I'm pretty sure I could tell these blades apart in a blind test. Astras are slightly less efficient. I guess that's a sharpness thing? I don't notice any tugging or difficulty cutting whiskers. It's just that after a pass, some of them are still there. The difference in smoothness is really noticeable though, especially on the first shaves. Rubies are smooth from the get-go. Astras take a shave or so to calm down. For me both are noticeably degrading on the 3rd shave though.