That's kind of tough. Neither is adequate for some jobs. Others (like how to pull trouble codes on my EEC-IV computers) Haynes does a better job. I also like how Haynes lists fastener torque values at the start of each chapter rather than with the repair procedure (makes it easier to look them up when that's all you're after). Still others procedures are better explained in Chiltons. Between the two manuals that I have, Chilton's has far better wiring diagrams.
One consideration: You may want to buy the Haynes, because the information in Chiltons is available on the internet (see the vehicle repair guides at
www.autozone.com). There's also another source (www.cyberpartspro.com/(something or another), but I don't remember the specific link.
Another consideration: You might also see what's available at your local library. They often carry Chiltons and/or Haynes manuals as well as professional edition (Mitchell, Motor, or other)
One last consideration: You can usually get factory service CD's for about the same price as Chiltons or Haynes from ebay. I know, it doesn't really help because it adds a third choice to the equation.
Go to the bottom of the page in the "related threads" thing, or do a search. This has been discussed a few times in the past, and previous respondents may have some other insights.
Hope that helps.
