Just a year ago I bought 100 Twin II blades for a little over 13 dollars, they cheapest you can find now go for 24.95. Twin Blades aren't that great. I just use to line up my mustache after I shave with the DE razor. I just wanted to do a minor vent. The prices are too high.
On the Gillette Guard, is it a moveable head? I use the Trac II for the sole purpose to get under my nose and line the top of my mustache. I can't tell from the pictures if the Gillette Guard is moveable or not.
On the upside, those blades go for $20 for a pack of 20 in the stores. Even at $25 for 100, you are still saving $75. Not bad for one and a half years worth of blades.