I've tried the P.e.P Pills a few times, had the originals, Twisteds and Loves. Twisteds are the best I'd say, I was getting pretty cool visuals on 3 of those before. I wouldn't buy the Loves again, they're pretty weak.

Also had the Head Fuel Highs "Red Rockets" - they felt exactly the same as speed to me. I've read good things about most of the Head Fuel Highs range.

Jax and Bolts are supposed to be good too.