Well first off, how many eggs would you want to hatch at a time? How much are you willing to pay? Do you want an incubator that is digital, or one you have to hand turn couple times a day? Do you want to constantly be checking it to make sure the temp and humidity is constant?
ETA: I'm looking into a "sportsman" because I've been using my neighbors styrofoam incubator and it sucks! The temp is always up and down around the 99.5 and stresses me out. The sportsman is 700 compared to the hovabator being 200 with the turner and air circulator. But it all depends on what you need or want.