2+ on the fluid trainers. I also had a Blackburn that I didn't care for. It was jerky and there was a noticeable difference in tension at different cadences.

I had a Performance Travel Trak that I liked a lot. After about 2 years of hard use (6 month winters around here) it started to get jerky. I called Performance and they're going to replace it. I just mailed it off 2 days ago. We'll see how long it takes to come back. But I do like that customer service.