I'm getting a blackberry soon, I'm upgrading my mobile to get one. I was going to get a wifi enabled smartphone but decided aganist it.
I've already got a wifi enabled laptop and a 3G data card, BUT wifi isn't always free or available when I need it, and because many of my emails come with lots of large attachments, using the data card to download them ennds up costing me a fortune, especially when I'm abroad, it costs me £7.50 a meg.
I think I'll use the data card when I need to email design work off urgently, when I've no other way of sending it and the blackberry for everything else.
I just went on a two week business trip where I was the only person without one and having seen how they work, (you get your emails in realtime, from up to ten web based email accounts, that humoungous 300k attachment is automatically shrinked to 4k, thus costing you less money), I think I'm sold.
They work everywhere, we went all over the place and they really do work almost everywhere. I can see the advantage over other gadgets.