Good deal Comms hopefully you will find something you will like.
Bottom line I don't think you could go wrong with any of the 3 garmins, it all depends on your requirements.

As for the Montana, I love my Montana, they originally pushed the hardware out before the software was ready. We are at 3.60 REV and I have contributed to one of the revisions. Garmin has been really great with any questions or problems I have had with in 16 hours max. Usually in under 8 hours most of the time. I had bought the unit with Lifetime US and EU maps. There is a cradle that you can buy for the car that gives the voice commands really loud.

Update history

http://www8.garmin.com/support/download_details.jsp?id=5335

Reviews

http://www.gpscity.com/garmin-montana-650-reviews.html

Comparison against Montana VS the new GPSMAP62STC (Half of the way points as Montana)

https://buy.garmin.com/shop/compare.do?cID=145&compareProduct=75227&compareProduct=89557

Also note, the max brightness of the unit with batteries gets even super bright when in the cradle. I have noticed that with my Dakota as well. Too bad you are so far out, I would show it to you if I wasn't so far out.