On my HTC Thunderbolt, I started with the Verizon protectors. I instantly disliked them - they are fingerprint magnets and I could not keep them clean, they always seemed cloudy. I went with Zagg because (1) I could pick it up at retail, and (2) the retailer matched Zagg's on-line MSRP (they had it priced $5.00 more for some reason). The Zagg feels different under the fingers; to me it's a "better" feel , but that is VERY subjective. YMMV.
I have applied and used Zagg on my kid's iPod 4 and on my work iPhone. Back when I carried a Blackberry, my employer supplied an Otterbox, and so I have just been used to screen protectors for a long time. I have had no issues with the wet application on any device; other than the Thunderbolt, none have removable batteries. In addition to the instructions, I apply them with the phone on a "bed" of paper towels to help catch the liquid when you squeegee it out.
When I first got the Maxx, Zagg didn't have a screen protector yet, and I had also recently acquired a Sero 7 Tablet and a touch-screen laptop. Skinomi had protectors for all three available. I have found that the "cure time" is longer as the screens get larger. I applied the Maxx Skinomi at bed-time and the phone was usable the next morning, but it still took a little time for the initial "micro cloud" - the screen looks pixelated - to clear up. Probably about 24 hours.
It took about 48 hours to clear up on the tablet, and about 72 on the computer, thought there was a small spot that took longer. The one on the computer seems to be MUCH more of a dust magnet than the other two. Don't know why.
Having used both Zagg and Skinomi, I would say they are comparable products, with comparable warranty policies, though I am sure the two companies would disagree.