The Bain Ultra air tub has a pretty good reputation, I've installed two in the last year. It has a remote blower that can be mounted up to 15' from the tub...so quiet and easy to access. Jetted tubs are more spa like...the jets provide more pressure than the air bubbles of the Bain unit. The pump is usually mounted directly next to the tub, so it needs an access panel for maintenance and repair, ergo, louder. Lasting longer is not usually an issue with either...they don't get used enough to wear out.

Just did a random search for Bain Ultra and came across this post. Ours was installed over 10 years ago and we STILL love it.

Personally, I prefer the more gentle bubbles of the air bath vs the jetted tub.

Some of the jetted tubs purge the water out of the lines to avoid bacteria build up, but not all. From what we have seen, most people have migrated to the air tubs for both cleanliness and the fact that you can use bath oils, gels, etc. without issues.