Compared to PSA, it's apples to oranges. PSA has the SAP, which makes their trip trading and dropping, then picking up more trips easier than envoy's trip trade system. But yes, envoy does have a trip trade and drop trip system. Trip trade works fairly well, if you know how to use it. I have traded up a full months worth of trips before. Drops on the other hand, are almost impossible these days, if you're trying to drop a few days in advance. You're more likely to drop a trip the day of, than days in advance. Having said that though, I have been able to trip trade to get the days off that I need when a complete drop was unavailable.
However, envoy's CURRENT flow is light years ahead of PSA's Selective Interview Program, as it stands today. That's not to say that it'll stay that way. I doubt envoy's flow will go away, as this is the basket that the company has put all of its recruitment eggs into. PSA 'might' get a true flow some day, but probably at the expense of their super trip trade program. But until they have serious recruitment and retention problems, AAG probably won't do it.

As far as the commute goes, MEM or BNA to DFW or ORD shouldn't be too bad. There's a lot of commuters in those cities, but they go everywhere that you would have to commute to PSA bases too, not just ORD & DFW. There's plenty of frequency, and most of those flights are in envoy, so as an envoy pilot, you will have JS priority. (IIRC, ORD-BNA is envoy, DFW to BNA is AA mainline and envoy in combination, MEM-ORD is envoy, and MEM-DFW is AA mainline and envoy combination). As a PSA pilot, you might be in decent shape commuting to CLT, but TYS would be a 2 leg commute, and I'm not sure about DAY, but I think that would be a 2 legged too. Not sure what other bases PSA is supposed to open, but I'm hearing PHL. Check Passrider Interline Travel Information ? Interline Travel and Pass Travel Information for commutability between any two cities.

You have my email address if you have any questions.