Over the past 12 years I have tried 4 different types of waders...I am a big man - 350lbs, comfort, and mobility are very important to me...and hard to come by. Here is what I have learned.... whether you are going to spend $50, or $500 the material you choose is the crux of the matter.
Vinyl - light weight, easy to move around, NO insulation, does not breathe at all....tore the knee on the 2nd day I used them.
Rubber - save it for the S&M scene, bulky, hard to put on, hard to walk, hard to wear, no insulation, and you sweat to death if it is the least bit warm. They will also rot and crack in a couple of years.
Neoprene - I had a custom pair made in the late 90's. They are OK to put on, a little hard to walk in, and if it isn't cold, you sweat enough that you may as well have bare-waded. They will keep you warm in cold water though, but overall, I suggest leaving the neoprene to the divers.
Breathable/GoreTex - this is my 2nd year in GoreTex...no comparison...hands down the best material out there. Light as hell, easy to put on and take off, loose and easy to walk in. If it gets cold add some layers underneath. You do not sweat to death because they really do breathe. Hodgeman has one called the guide light or something like that...under $100.
I suggest always buying stocking foot waders, the boots on the Boot-foot waders are bulky, heavy, do not keep you warm, do not fit well so your foot slides around when you walk, and they make putting the waders on very awkward. the ridgid seam can also irritate your calf very badly if you have long trek to your spot. With a stocking foot wader you can select a nice pair of affordable, VERY lightweight wading shoes that tie on securely, and give you a much more comfortable time when walking to your hole, or wading in the water. Adding a 2nd layer of neoprene sock to a pair of hunting socks, and your feet should be warm even in sub freezing temps.
Noam