Mine is a combo - fluid/magnetic. Works well and the power curve is such that you use the gears to adjust tension. With that said I am in the same camp as DF - I HATE IT!!!!
I push myself to ride in the cold until there is ice and snow on the roads and then I stop.
I have not tried spinning classes but may do that this winter.
With that said - many of my friends like rollers, I have never tried them. But I still think they hate them.
One thing to note - on a trainer you get a much better workout - there is no drafting, no slacking off. I would say an hour on the trainer may be worth 1.5 to 2 on the road.