Got the full body kit and put it on 2 day ago... except the bottom piece (I'll explain little later).
Yes it is a bit glossy but I think it looks good. More than compensates for it's protection and helps with grip as well - I've almost dropped the MBA twice already because of it's slippery aluminum cover.
I have the invisibleshield on every thing worth protecting in my collection of gadgets. Including, MBA, MBP, two MBs, iPhone, and several cell phones.
I absolutely love the invisibleshield. I've never been disappointed with one and God knows how many times it saved me from drops (things onto and dropping on the floor).
The MBA cover didn't disappoint either. I could only install the top cover, wrist cover, trackpad button cover for now, because the bottom cover was mis-cut (the cut was flipped over as if it was looking in to a mirror - in other words, adhesive on the wrong side). I called Zagg the next day, and no problem, they sent me a new one and it's on it's way.
To answer the trackpad question... The trackpad cover is a separate piece, as is the trackpad button cover. The trackpad cover is the only thing I don't like to cover, because it's a bit tacky and hinders finger sliding. But, my son doesn't mind the tackyness on his MB trackpad. Matter of preference, I guess.
You also, have to remember that the covers have a life time warranty and will exchange if you damage, peel, or if you send it for service and have to remove the covers. You just have to send the old cover back to them and they'll send new ones to you! They peel easily with a firm pull. No glue residue, even after 1 year, in my experience. btw... excellent customer service.
I highly recommend this product on all your stuff.
quick install tip: Make sure you spray lots of application solution (heavily mist evenly). Match one side and slowly lower the rest of the cover (if you get bubbles inside, don't worry, you can squeegee it out later). If you have sprayed enough solution, you'll be able to slide the cover until you position it right. Spray lightly over the top (this is to help the squeegee slide easily without moving the cover out of position) of the cover and hold one side of the cover firmly, so it won't move during the squeegee process and squeegee the solution out. After you squeegee the solution, wipe the excess solution on computer and work area with a lint free cloth. The curved edge will not be tacky when wet, so squeegee out as much solution as possible and let it dry for 3~4 minutes and push down with your fingers (or finger covered with lint-free cloth - helps absorb excess solution).
First try a cover that won't show too much if you mess up (the bottom cover, for example). Gain experience and the rest should be easy.
Just be patient and try to work in a dust free environment. After all the covers that I've installed, I can cover a whole computer in less than 15 minutes.