Why are you on the market for new waders if you already have Simms? Do you just want something different, or is the size an issue (mine are tighter than they used to be)?
I know some people's size/gate is an issue, but they're the best fitting waders I've worn and with their lifetime warranty, should last you forever.
I bought a pair when I was 18 years old, wore them hard for 10 years (fishing & public duck hunting on the coast) before a seam started leaking. I sent them in for a warranty repair, but they decided the seam couldn't be repaired, so they sent me a brand-new set for free... I've now been wearing that set for 8 years without a leak or issue to speak of.