I have the TomTom 310 at home and a 510 at work. I got Dad a Garmin for Christmas 2 years ago. In general, I like TomTom but the Garmin had better places of interest (gas stations, resteraunts etc) & that was better for Dad.

Map upgrades on TomTom are a pain in the butt. I haven't tried it on any other brands so I can't say if they are any better or worse.

You have the right approach though. Find one with the features you want at the price you want to pay. Use it & enjoy. Don't second guess your decision.