The great "Which Sat Nav" Dilemma!!!

I am currently looking to upgrade my Sat Nav for use when towing my caravan around UK and Europe.  I was initially impressed with the specifications of the Club sponsored Snooper S6450 especially the fact that it came pre-loaded with all UK Club Sites, Caravan Europe sites and ACSI sites throughout Europe; 20,00 plus sites apparently???

However I recently borrowed one from a friend and became very disappointed with some elements of its functionality.  The pre-loaded sites were excellent however the touch screen sensitivity was very intermittent (had to use the pointer provided as finger sensitivity was very poor), map scrolling was very poor and Post Code navigation was not very accurate (despite saying it used full 7 digit Post Codes it only took you to the street concerned not the house/building required).  Garmin and TomTom are very accurate as they take you to the house/building concerned.

I therefore have two questions:

1.  Is it possible to download (or buy on CD/DVD) the vast library of sites detailed above that are pre-loaded into the Snooper from the internet for loading onto another brand of Sat Nav? If so please provide the necessary link.

2. Is there another Sat Nav that is recommended for the caravanner that is better than the Snooper?  Garmin looks ok but does not have the same quantity of site info pre-loaded!!!

Cheers.