Blackberry 8700g Wireless Handheld

I've just been told I am getting one of these at the end of the month (on the O2 network) to replace my current company mobile phone.

I've never used anything like this before. Apparently I get emails automatically (we use Lotus Notes) and it works as a phone, calendar, web browser etc.

I guess one disadvantage is the size of the thing - although my current phone is a Nokia 6680 (quite big but I run Tom Tom mobile on it) - so less of a change for me than the guys who have Motorola Razr's!

Does anyone else use this sort of device? Comments / advantages / disadvantages / useful tips / recommended add-ons etc please.

Cheers in advance.