TTT isn't a bad album, the era itself was just so underwhelming and rushed. It came and went so fast, i didn't even have time to love the album because i was stilling using LOUD and then suddenly Unapologetic was here. Such a filler era.
Between GGGB, Loud, TTT and Una i dont think any of them are remotely 'bad' albums. It all depends on your musical preference. I personally find myself listening to GGGB the least (sans Umbrella and Rehab) but i still appreciate all the other tracks.