I'm a die-die hardtail bridge user so I'll explain the pros and cons I've come across. I also used a non-locking, dive-only tremolo before so yeah I'll add some of that too. Basically, I dislike tremolos, both dive-only and free-floating, but its my personal preference.
Pros:
- Better sustain,
- Simpler to re-string and retune, as there is no locking nut, and bridge does not move and upset the tuning,
- More stable than a dive-only tremolo with regards to keeping in tune with heavy usage,
- Because the bridge does not move, you can downtune or uptune one string and the other strings are not affected.
Cons:
- Cannot whammy and cannot dive-bomb,
- Less stable than a free-floating tremolo because there is no locking nut. If tuners are crappy, guitar will go out of tune very easily, and thus hardtail bridges require good tuners.
Well, not going against tremolos but I just don't like them, and I don't need them either.