That's a good unit but you'll have to replace the SLA batteries in 5 years or earlier. Those batteries will cost more than the price of a P11VNT3. Each UPS rated to about 750W, whereas many passive surge protectors are rated to a full NEC single branch circuit, about 1850W.
spikes and surges: surge suppressor
voltages irregularities: voltage regulator
power failure: UPS
The cost of those from APC is roughly, $30, 60, and 90 each respectively. The only issue is UPS have high maintenance costs for the batteries, see reviews at Amazon for LE1200 regulator.