PDA advice

[lethargic_man]

My father's toying with the idea of getting a PDA. Possible options under considerations are the Nokia 9300i, HP Ipaq or Sony Ericsson 990i (he wants something compatible with Outlook and exchange files). "This is where you might be able to help," he says, "by asking any of your mates/colleagues who have one, what they think of it." He adds, "My requirements are for a unit with large-ish buttons, eg Nokia, and/or a stylus. I can't be arsed with tiny, cramped buttons which require a fingernail to operate—my fingers are just too chunky to do that—I've tried it in shops. User opinions would be helpful."

So, any advice for him?