I currently run a One Stop Slot Shop OS3 controller in my HO racing. But I've borrowed Ttuspeed BPIIs to try before and I think I actually drove slightly better with them.
I'm ordering one next week for my son to use (he currently runs a DS3) but might spring for my own as well!
Really nice controllers and I think the price is incredibly reasonable for what you get. All of that additional tuning compared to the DS3 for barely double the price seems pretty reasonable.
If your interested in getting the best out of your TRUSPEED then The Wirral Slot Car Club are holding an event which includes a presentation and a workshop hosted by Steve Hills. Please see attached.