There are a few threads in here about it with people's reviews on the various models, just do a quick search.
For me, I have tried all kinds of GPS stand alone units, and what I am currently using is what has worked for me the best (I used it on a 2 week trip around Portugal / Spain)
Cheap Ipod or Iphone (If you don't have one, buy it used on ebay) and the Copilot GPS app
To me having Offline GPS capability is important for when cellular reception is not available.
Yet to find a stand alone device that will have all the features and portability of this option.
Price wise a good GSP with all the features you want will run you at over 700 bucks, the ipod/Iphone solution could cost you less than 300 bucks