Like rexcramer said, its quieter, warmer and gives the car a different look. It makes driving in wet and cool weather a much more comfortable experience. Sound wise, it's different, less wind noise as you would expect and I find the engine sound more muted, but very nice to hear. However my hearing is really poor from too many rock concerts in the 70's...
The large rear window in the hardtop give good rear visibility, much better than you have when the soft top is up.
I doubt you would regret adding a hardtop.
