I've got a Garmin 595LM and I would NEVER recommend it. For the money, its horribly over priced and under spec'd. I've'e bought a second battery as I thought the original was faulty (it wasn't), just won't last five mins off the bike. The display is terrible - I didn't realise how bad until my mate showed me his BMW Navigater. The difference is well.......22inch B&W tv compared to 42 in LED Flat screen!!!
I've'e been saying for ages, that my next bike will just have a phone holder, now data roaming charges are gone, I'll stick with my iPhone on a holder.
Sorry to be so negative, but got to speak as I find, no experience of TomTom.