I find garmins algorithm works better than mcgellan and tomtom, so personally I'd stick with garmin. Although for some reason they still don't do it as good as google maps/navigation for android, but if you're in the city it works fine anyways, in the country it'll send you on dirt roads and stuff
As for features/prices I have no idea!
Canadian tire usually has good GPS sales, should be able to get something decent for $150 these days
EDIT: I know I said garmin, but here's a nice tomtom on sale with lifetime maps for $150, although it's 5"
TomTom 1505M Automotive GPS | Canadian Tire