Hi Diane & Marshall
We have a Garmin StreetPilot 330 and a nuvi 255 and like them both.
Garmin provides free software upgrades to both via the internet and USB cable.
However you have to purchase map upgrades.
We just got the nuvi 255 and Garmin provided 1 free map upgrade but you had to use the updated within 2 months of when the unit initially acquires satalites.
Both provide the capability to download custom POIs to the unit from your PC using the USB Cable.
I downloaded and installed a POI Loader
program from the Garmin web site that I accessed & found on the POI Factory
web site. This POI Loader is sepcific to Gramins and works great for dowloading custom POIs to both of our Garmins.
I also downloaded many of the custom POI files from the POI Factory
Iíve also made my own custom POI files, theyíre just simple 3-4 column csv files that can be easily made using Excel or a similar spreadsheet program that gives you the capability to save the file as a csv file. Column organization for custom POIs is Long; Lat; Name; (I put a 4th column for full address & phone number Ė this information is displayed on my StreetPilot but not on the nuvi).
We like the Gramins and are happy with them. Which model to get is dependent on your price range and the features you want. We picked up the nuvi 255 at BJs for a little over $100 on sale. Then thereís the novi 465 that runs for around $400 (mabe more), has a lot more features, many which are applicable to RVers. So, as Iím sure you know, thereís a wide price range and features.
When traveling I still do not rely 100% on the Garmin - I still like my paper maps. But I have grown to appreciate the information it provides and it has helped when finding a campground when we are close and are on local roads.
When using our Garmin to help find the campground, I rely more on the custom POIs that I've created and have verified the Lat & Long using a MapQuest Lat-Long
I can't comment on any of the other brands, because I've never used them, nor do I know anyone that has one.
Hope this is of some help.