> Is Goodxxx popular?
> So then, you'd probably want to get rid of roms with "o" and "b" in them? Because
> there's something wrong with them? And go for roms with "!" and if you don't want
> hacks then also replace roms with "h" in them. Any other bad letters I should be wary
Good sets aren't popular nor common like before. However they're worth it if you're looking for game translations [T-xxx], public domain homebrew (PD) and unlicensed titles (Unl). The tool was meant to identify overdumps [ o ] and bad dumps [ b ], however instead of discouraging their collections people used that information to collect everything. Hacked ROMs [ h ] are a bit interesting because while some only showed warez group intros, some others had trainers that allowed you cheat in times emulators didn't have cheat features. Kind of worthless in current times except for the historical and nostalgic value.
If you are looking for only verified dumps and you don't want homebrew software or fan translations no-intro collections are a best alternative for you.