Yes, as with other types of bikes, there is a noticeable difference between low-end and high-end models. But whether the differences justify spending the additional money is something only you can decide. If you haven't ridden a fixed gear bike before, start with a used or less expensive model so you can be sure you like ridding fixed and that doing so will fit your needs. If you're going to be leaving the bike locked outside, don't bother looking at high-end models as your bike, regardless of model level, is likely to be stolen, stripped, or vandalized at some point. If you can bring your bike inside your home and workplace, a higher end model may prove to be more satisfying in the long run.