UPS Recommendations. Online or not.

[Cwill]

Thank you all. Your experience is much appreciated!

 

[Epy]

Late, but +1 for Phoenix Contact UPSes. Had good results with them.

-1 to SOLA, we almost always have to re-solder the terminals on the SDU500s because they break easily under a tiny amount of vibration.

 

[Remrun]

Might want to think about installing an external bypass and isolation switches so you can replace or work on it on the run. At the currents you are talking about this shouldn't be a big deal. Also get something that has external batteries that can be replaced on the run.
My biggest problem with any UPS is that everybody forgets about them until the batteries fail and you need it. Depending on the battery type you either have to replace them every few years (like the type you will likely get) or with lead acid style the water levels and temperatures have to be maintained.