Why? There's no comparison between the two. Envoy has a much bigger infrastructure and more facilities. If that's what you're looking for more power to you.
What you should be looking for is the best QOL while at a regional. When I picked my regional it was location of bases first. Being close to family and friends can make your stay at an airline even a regional much more enjoyable. Who gives a s*&^ about facilities and infrastructure? All 3 WO's offer the same. Good Upgrade time and a job at American. If you chose one I'd go for best commute.