Welcome to the forum. I'll share some thoughts on waders with you based on personal experience.
First, nothing that I have tried breathes better than Gore-Tex. If you were to go with regular waders vs. waist high, I am convinced you will be more comfortable with waders made of Gore Tex. This puts you in pretty limited company though, Simms and LL Bean are the only 2 companies who have licensing to use Gore Tex in their Waders. I'm not sure that LL Bean has a Gore Tex wader these days. Simms now has a pair of Gore Tex waders for $299, the Headwaters.
Then there are the rest of them. Some breath better than others and some have more layers than others. I would stick with one of these three brands if you are not going the Simms route. Orvis has excellent customer service and does provide wader repair. I had a pair of 4 year old waders that I sent back to Orvis and they repaired them for nothing. My cost was shipping to Orvis. they paid for the return. LL Bean has a legendary satisfaction policy with anything you buy from them. Patagonia is much the same as LL Bean. Though I have never worn Patagonia waders, I know their warranty is iron clad. The whole point here is that I would recommend a brand that has a warranty that you can live with. You might find a cheaper pair of waders, without a warranty. If a warranty/repair are not important factors then your options are even greater.
Lots of folks are raving about the Reddington waders these days, I have not used them. They have licensed Orvis' sonic welding technology, which means no stitches, they are all welded seams. The thought here is durability. No stitches means no pin holes on the seams.
Depending on your location, which seasons you fish in and a bunch of other factors, waist high might be good or it may not. As Ard said, there's always that one spot, or there's always that one time when you might be out on the water and the stream level rises. Or that may not be a factor at all. Do you do lots of bushwhacking? If so, you might want waders that have reinforced pieces in the legs, knees, etc.
It depends on your perspective, but I am all about comfort. If you factor the price of your waders over 2-3 years it's not as bad as some might think. Some folks prefer to buy a cheaper pair, and that's perfectly OK. Buy something that fits your budget and gives you a GOOD fit, whatever the brand and style. What's most important is that you put them to good use! Also, you could go the route of 2 pair, one waist high and one regular---again, depending on how much you fish, seasons that you are fishing in, etc. Wear one pair, then switch to the other. The good thing about this is that you always have a backup.
FYI, Orvis has some new waders coming soon, so if you can wait, you might be able to take advantage of a closeout or get their latest technology depending on your preference. I have always been happy with Orvis waders. I got 4 seasons on my last pair of Pro Guides before having to send them back for repair and replacing them with Simms G3's. After wearing those, I am not sure I can wear anything other than Gore Tex.
Let us know what you end up with. Happy shopping.