Installation was a breeze. Anyone used to applying products like WriteRights to their Palms, Pocket PCs, and other touchscreen devices from days of yore know that it can be a harrowing process fraught with dust particles, alignment issues, and impossible-to-remove air bubbles no matter how careful you think you're being, so the Crystal Film is a breath of fresh air in comparison. Somehow, the film seemed to basically suck itself into place as soon as it started to touch the phone, so all we had to do was make sure it was appropriately aligned. Getting it lined up was easier than your typical screen protector thanks to the film's cutouts for the earpiece and home button.
On our first attempt, the alignment wasn't perfect. No biggie; Power Support recommends using cellophane tape to lift the film back off the phone, and that worked like a champ. Wash, rinse, repeat -- our second attempt was much more successful. The film can be removed and reapplied repeatedly for cleaning, though we imagine that won't be necessary in practice.
Once appiled, the film was barely noticeable to the eye (in fact, it would've been impossible if not for the seams around the button and earpiece). The feel of the film was almost indistinguishable from the naked screen for gesturing with our fingers, which we think is absolutely key to a product like this having any sort of commercial success.
Bottom line: probably not necessary, but if something like this helps you sleep a little easier at night, you won't regret the purchase. The installation process won't raise your blood pressure and once it's on, you won't even know it's shielding your precious cargo from sharp baddies.