To be honest, I always found Ijji's games enjoyable. I played Gunbound and GunZ both for a good long time.
Gpotato though, I will agree on. They released some game... It's been so long that I don't even remember the name. It was so buggy, and so laggy, that it was near unplayable. Could barely stay connected without DCing every 3-5 minutes and most of the items were missing, quests were bugged, and yet they had a giant cash shop with items for functions that didn't even work and gear for levels nobody could obtain cuz of the bugs.