Posted for "Tom Gourley" <tom.gourley@verizon.net>:

 Op's standard offering uses the Crossbow 420.  You can, of course, upgrade to
the Crossbow 500, which is another several thousand dollars.  An interesting
bit of information is that the 420 gives you a WAAS capable GPS while the 500
does not use GPS.
 
From what I've read on the net Direct To is recalling the 425, not Chelton.
 Also, Crossbow is continuing to develop and test a fix for the 420/425.
 
 Tom Gourley