I cant vouch for any particular make, but the main points of a UPS are :-
1) Get a bigger battery than the one supplied. 2) Change the battery every 18 months/2 years 3) Test it every friday night after you've backed up your data. At the first sign of a hiccup, check the connections and change the battery !
People buy these things, stick them under the desk and forget about them. They are invaluable but need some TLC. Good luck.
I use an APC SmartUPs for the server at work. It's 5 and a bit years old and I have just had to replace the batteries. It literally saves our bacon every week as our electricity supply is variable, to say the least. If I watch the UPS for any length of time (I know, it's a strange pasttime) I will see the supply go below the acceptable level and well above and the ups kicks in and out as needed. The batteries would probably have lasted longer if the supply wasn't so rubbish. For replacement batteries I have found this company excellent: UPS Systems plc, Charnham Street, HUNGERFORD, Berkshire RG17 0EJ
but cannot remember anything more than a passing reference to UPS's.
At the back of my mind, I seem to remember asking FE to consider a full length article sometime in the early years of the Millennium and something about a lack of Review Models. We had had a Power Cable severed nearby and my PC had naturally crashed.