Even on EDGE the data speeds can be quite crappy, quite often because of the backhaul it has to do to get to the actual internet gateway on the operator's network, if you are in the middle of nowhere. So going for a GRPS-only phone will only make it even worse.
no issues faced till now. I am using 512 MB microSD card with it. Battery is okay, lasts easily 2-3 days with normal usage (with mild music/radio/web browser use). Radio and web browser tend to consume more of battery power.
One suggestion. buy the phone from Hot Spot. They are giving 2-year full insurance against all possible damage to the phone for 250 buck, including coverage against damage caused by moisture (though not coverage against theft).