I use the antiglare. Had one on my iPad 2 and now on my new iPad. I'm sure it degrades the display some but I personally can't tell the difference. I really dislike having to twist and turn to get out of glare plus the anti-fingerprint properties are great.
They are really easy to put on, took me all of 30 secs or so for a perfect installation. Just get everything ready before hand and take your time.
I'm sure the antiglare is not for the 'purists' out there but for me it's the best. If a crystal clear display is more important to you then go for the Crystal.