If you can afford one, I would strongly recommend going with a dual-conversion UPS. A line-interactive UPS like the one you posted essentially acts as a pass-through for your mains power until it detects a power loss or a brown-out. This works most of the time, but there's a short delay during the switch from line to batteries (just guessing, but most likely on the order of milliseconds). This might not sound like much, but you're counting on the capacitors in your server's power supply to hold enough charge until the UPS kicks in.
The other thing to consider is that a dual-conversion UPS also supplies "clean" power to your equipment. It essentially acts as a DC power supply connected to an inverter, so regardless of how bad your input power is, you're always going to get the correct voltage and frequency out. I connected my old line-interactive UPS to a cheap generator at one point; the voltage and frequency regulation was so bad on the generator that my UPS continually switched on/off of battery (several times per second), and the equipment attached to it immediately shut down.
I can connect my dual-conversion UPS to the same generator, and it keeps humming along as if it was connected to mains voltage. According to the datasheet, anything from 60VAC to 150VAC, it's still going to output clean 120V/60hz power.
They're much more expensive. Mine is 1000VA, and if I remember correctly, I paid something like 600 or 700 USD for the UPS. An add-on rackmount battery pack was another $300 or so. It was well worth the cost, though.