There is a fantastic deal on a particular Trip Lite right now... The Smart700USB model. It's got the same power rating as the regular Smart 700 models, but it's only about $120 which is like half price. Why? I talked to two Tripp Lite reps and they couldn't tell me, but they both figured it was because it's a new model.
I haven't heard any noise from these units, but they're just installed in offices so I haven't paid much attention. My only complaint is that they throw off a lot bad vibes so they have to be at least 4-6' from your computer monitor....probably because they're plastic. APC units are of better overall construction, but tons more expensive.
One good thing about tripp lite is that they really stand by their products. The reps I've spoken with were very honest and to the point, saying that are striving to compete with APC. I like that attitude.
At work here I've got about APC Backoffice 420's and 280's running most of the show, and only recently switched to the Tripp Lite Smart700USB because of the price. They are much cheaper in construction than the APC's, but for the price they work well!
I have to setup a new system today with one of these tripp lite units....I'll plug it in and let you know if I hear anything.
Slackmaster 2000