can"t tell which one to buy, I'll share my experience.
I use a Garmin,(10 years ) I bought a Tom Tom . people said it's east to transfer google route maps to it :( i can't do it.
Hate it because the trye software is totally different then Garmin.
I can't get it to plan routes or way points. I'm ok on computers, but I hate the tom tom , wasted 350 dollars on it.
my point is if you like the way Garmin is in routes and maps and going from computer planing to the gps . Stick with the same brand name you have. I hate my Tom Tom , it was a big cash hit to me to waste 350 dollars on it.