For me it's that the app consistently has errors recognizing my custom location (D:/Games/Epic/) and will lose the games in the launcher. Well, no big deal right, just point it to the location again?

Nope, no way to do that. Alright, well, reinstall the game where it already exists and it will discover the files?

Nope, can't install a game to a folder containing files. Alright, so then you have to move the game install folder then install the game then cut/paste the existing game files to... you get the picture. Most of the time I just end up having to redownload the game.

That aside, the program takes forever to launch and seems to use an obscene amount of resources for providing absolutely nothing to the game experience. Actually using it is tedious since there's no way to set a homepage that isn't their store (from last time I checked at least) and I experience a weird flickering issue along with some weird resolution scaling? It made it really hard to read the game details which seems important if you're trying to find one of the free games to play.

It's just a whole combination of frustrations that just make me question why I still have it installed. At this point I'm only still claiming games in the off-chance it's a multiplayer game I already own with cross-server support. I have a second Steam account for games I come across for free that I already own - games like Killing Floor, Payday, all those sorts. You never know when it comes in handy having an extra account for some local LAN play, so I've used the free games with the same philosophy.

All that said, you get around this using Heroic with the benefit of padding out a game library.