I would highly recommend a fluid or wind trainer over a mag trainer. We bought a cheap mag trainer off craigslist and while it worked, the "feeling" was so bad/unrealistic/downright not fun, that we never used it and finally sold it. This year I splurged and got a fluid trainer (Cyclops, but Kinetic and others are good too) and am much happier with it!

I suppose with Nashbar you can return it, but trainers are so heavy that the shipping costs are worth considering..