I did mine myself with Monstaliner a few months ago. It was kind of a pain, but very well worth it. I will never go back to carpet. It's easy to clean, it won't fade, and when (not if) it gets wet, I can either towel dry it or let it air dry and nothing gets musty and moldy. I can make it look brand new with a bottle of simple green and some rags. Try making carpet look new after awhile. I get compliments about the looks of it all the time. Finally, for those concerned about noise and heat- neither are an issue. It isn't noticeably louder than when I had carpet. I've also driven 6.5 hours in it nonstop (well, except for gas obviously, lol) and while the floor does get pretty warm around the exhaust area, the liner holds up fine and it isn't so hot that it would burn you.
Do it- you won't regret it. I don't know why Jeeps don't come stock that way, but in a way I'm glad because I absolutely love the Monstaliner that I put in. Can't say enough good things about it.