Totally a DIY. A detail shop, that knows what they're doing, understands that doing this job properly could take up to three hours. There's lots of prep like washing the car thoroughly, wiping down with a claybar, and spot removal for tar and other crap. Wash again. The detailer is not going to be as careful as you since he's got other cars to do and he's going to charge you big time. And of course they keep the tools that you could have bought yourself and used many times again. Now a true expert detail shop could use a rotary buffer (dangerous in the wrong hands) and get the job done in two snaps but they're not cheap either since it has to be done with skilled labor and not some guy they trained in five minutes working minimum wage.
Reminds me of the saying about giving a guy a free lunch vs teaching him to fish.
Detail shop rates are steep
You can get a Menzerna kit about $250 with a Porter Cable orbital buffer or the higher end Flex buffer kit for $500. Comes with everything, pads, polish, etc. And maybe an inexpensive Craftsman halogen lamp. I saw a guy with a LED light attached to his head like a miner -- pretty clever. There are a ton of YouTube videos that show you the proper orbital buffer method. the key is to use the swirl remover sparingly and take your time moving slowly covering an inch or two per second.
this video shows the proper "L" movement.
Menzerna SIP + Meguiars 7006 Test panel - YouTube
kits
http://autogeek.commerce-search.net/search?keywords=menzerna+kit