Just jumped into this discussion.
I have a subaru35 on a staton axle mount, a honda 50 on a staton friction (with a Dax carb) and a super Titan on a bmp friction drive.
My $.02 The Titan is a good engine, but the Honda is great. I know the Titan is half the price. I'm not saying the Honda is twice as good, however I whole heartily recommend
The Honda. I have built two more bikes (for friends) with Hondas.
As far as power and torque, it is hard to give exact results. All the bikes I have and have built are different. Doing a drag race isn't really a fair comparison. I have tried the Honda then the super Titan on the same bike with the same drive system and the honda fells about 10-15% more powerful.
The Honda has a over all "great" feel.
The Titan has a "good" feel.