Compass will be losing the AA flying. This will result in increased upgrade times. Envoy has a lower QOL but you will upgrade sooner, and have flow in your back pocket.
Another consideration as a commuter is travel benefits. As an Envoy pilot you have the same travel benefits as an AA pilot, including non-rev priority on all AA/AE branded flights over offline jumpseaters and non-revs. The AA travel benefits will also allow you up to 13 friends on your travel list in addition to the immediate family. The immediate family will also come before offline jumpseaters and non-revs.
If AA is on your target list, your time at Envoy will also count towards earning lifetime AA travel benefits... you can’t get lifetime travel on a mainline from subcontractors.
Then there’s the whole “all regionals are not alike” thing... which unless you’ve worked at more than one, or specifically gone on a side by side comparison may not be so obvious, but is definitely true. At some regionals you’ll be doing manual W&B for each flight, and at others they’ve been doing EWBS and ACARS for TOLD data for decades already. You’re also hitting at a time when the shortage is expected to draw the flying back into the mainline and their wholly owned regionals. Keeping the flying in house will keep the upgrades moving and the new hires coming to where the movement is.
Do your research carefully in this emerging market.