like i said earlier, i tried other portable GPS devices, and
most of the portable GPS have 3.5" to 4.3" LCD screen; which was
too tiny for me. i think mio moov 500 & navigon 8100t have 4.8" LCD screen. Pioneer F series have 5.8" LCD and I love it. Size matter for me, but its just a personal preference.
Garmin has relatively small(?) LCD size which is 4.3", however garmin's LCD brightness is excellent. I was able to use garmin under direct sunlight.
Navigon & Mio Moov displayed lots of information on screen, and i liked those a lot (such as, US speed limit, giving u speed warning without modification, ETA, miles to destination, etc) These unit give u more options compare to garmin nuvi. Navigon's voice command was useless.
If u already have a decent audio unit w/ mp3, ipod, video feature and do not care about size of LCD, then you will be fine w/ any other portable devices in the market these days.