I have a Magellan Explorist XL and I find it to not only be accurate but also easy to use. The large color screen makes using it a dream compared to units I've tried with smaller screens.
I think, for me, one of the most important aspects was expandability. The XL can use XD cards. This allows me to store maps, caches, routes, etc. of many different areas with less fear of losing them because of some issue with internal memory. The external card has been most valuable when I've upgraded firmware on my XL. I didn't lose a single piece of data because I've been storing things on the SD card from day one.
I only have one problem with Magellan. I had to call to return a piece of software and they wouldn't reimburse me for shipping or pay to have the software shipped back ... so in the end I was out almost $20 between shipping both ways. I'd ordered the software from their web site. They indicated that Worldwide Basemap was the replacement for DirectRoute Europe. I'd wanted DirectRoute Europe for my trip to England and Italy a few weeks ago. Needless to say ... Worldwide Basemap is exactly that ... only a Basemap with no more detail than the built in basemap except maybe that you can get a basemap showing the ring road around London.
When I returned the software they said that if I change my location to UK on the web site I'd be able to order DirectRoute Europe. That didn't turn out to be the case. SO, basically ... it's useless for Europe if you want to display any kind of detail on the unit.
Oh, one other comment ... about the units with a built-in compass. I've never used one with a built in compass, but there are times I wish mine did have that ... like those times I forget to grab my real compass out of the bag.