There is still decent angel support out there, as much as it can be given APS is long dead. Brad is obviously great and there are a few others who either make parts or can service.
https://www.pbsports.com/collections...intball-sports
bought the remaining stock of angel parts when APS shutdown so for older angels they might have some replacement parts if needed.
Angels vs new markers?
Most modern stuff looks the same because it basically is. There are two designs, poppit and spool but these days they both come in a single tube design. The improvements are almost entirely around simplicity and reliability. They've unified the valve and bolt systems and there really aren't rams hitting valves in anything modern. This results in less parts, simple disassembly (modern markers can pull the whole drive out and have a clear line from back of the tube to the barrel) and higher reliability. Efficientcy will be better than an older angel but that's not super relevant until your shooting several pods a game in a big game.
I love the mini gs. at $330 it's hard to beat. From that price point up you're really just looking at nice to have features. ex: tool-less disassembly (luxe), better eye access for cleaning / exchange (axe, dye, luxe, etc) OLED screens (dye, etc), slightly different frame lengths and cute stuff like wireless charging and rechargable batteries.
There are opinions on spool vs. poppit depending on playing conditions but my sense is it's pretty minor one way or the other.