What size is your tank and what are you thinking of putting on the UPS. Usually, it is recomended to only put "critical" devices on the UPS such as skimmer/return pumps so you can maximize the battery life. Depending on what all you plan to put on it and how many watts they are drawing, there are a lot of choices. If you have a larger tank and are drawing a lot of watts, I personally beleive APC is the only way to go. I wouldn't spend the extra money for a smartUPS version since the pumps aren't too sensitive to minor power spikes when switching to backup. If you are only trying to backup a smaller HOT skimmer like a Remora or CPR, then you can pretty much get away with whatever inexpensive unit you can find since they are only drawing about 30-40 watts. If you can give a little more detail about what all you plan on backing up (and the wattage if possible), I am sure that a lot of us here could help recommend a decent unit to go with. We also need to know how long the power is usually out. If it is a lot of 2-3 minute outages, that is completely different then if the power is regularly out for 30mins or more.