First - I never had a pair of Simms waders I didn’t like. But the first pair of waist waders I bought were on a tighter budget and I got a pair of Scierra waders. I’ve been very satisfied with both function and durability so I never switched brands.
My first pair were called CC3, the second X-16000, now they call their line X-stretch. Same design, upgraded technology and materials. Don’t know if they are available on the US market, but I know they can be had on Amazon or Ebay.
At a third or better of the price of a pair of Simms I’ve gotten used to keeping a pristine pair for fishing trips, a more used pair for bushwacking around the local creeks and a beat up pair for conservation work. I only recently retired the first pair for good - still no leakage from any seams but one of the front pockets totally wore out on the inside after ca 10yrs and I got tired of putting stuff in the pocket and having it find its way inside the wading sock/boot. (they also had the general apperance of being used for sanding down rusty metal and were spotty, miscoloured and had both gravel guards torn by barbed wire, so it was about time)
My experience is that you can get away with less than top of the line breathability in a pair of waist waders, at least in temperate climates. Details like zippers and pockets feel more important than on a pair of chest waders, as well as durability on knees and the rearmost area.