The APC SMC 1500 would be the better UPS primarily because the output waveform is a true sinewave. And if money were no object, that is what I would opt for.
But you really don't need that advanced technology to protect your systems and data. This is because all computer equipment power supplies are designed to function well when powered through a surge and spike protector, which works by chopping off the tops of the sinewaves anyway. So if you buy a "good" UPS with a quick cut-over, you can buy an UPS that provides a "stepped approximation to a sinewave" for your computer system with no worries. Quality, properly functioning, consumer electronics power supplies can handle those not-so-pretty chopped off sinewaves, if not extreme, with no problems.
But again, I said a "good" UPS, not a cheap one.
So your biggest concern is cut-over times, stability, and runtime. A cheap UPS may not have a fast enough cut-over to prevent disruption, and then may not be the most stable.
I am not rich, so I did not opt for a $400 UPS. Instead, I have a APC Back-UPS XS 1500
protecting my main system and note it provides at least 15 minutes of backup power for my i7, 8Gb computer, all my network hardware, and both of my 22" LCD monitors with aplomb. And the cutover time is so fast, I have never had a power disruption - even after squirrels forget to let go of one line before grabbing the other, sending themselves to crispy critter land, blowing the transformer fuse in the process (a too common occurrence in my old neighborhood).
That said, I note that Cyberpower claims it provides a pure sinewave output at basically the same price as the less expensive APC UPS. APC has the more established reputation as a quality UPS maker, but you pay a bundle for the name too.
NOTE: Remember...CyberPower CP1500PFCLCD is not available for purchase in my region.
Ummm, then why list it, or have it under consideration?