In my opinion, this is a PDA with the phone feature. There are pros and cons. I've got mine for 3 days and I've probably loaded some software(still to work out what) that practacally kill the phone feature because when ever the PDA side of the device makes a sound, ring, click, changing volumes, I can no longer here anything when I am in a call, non does the other end hears me. O2 just exchange the unit because it was pretty much DOA. The Unit is great, but don't download the o2 Plus software. It just slows the PDA down to a halt. Keep the today screen to the basic and everything should be fine. I think there is some issues with the Blue Tooth, but haven't exactly worked out what it is. The volume control slider is loose... (that goes for both faulty and replacement unit). And the replacement unit was tighter when I got it out of the box, but quickly became loose.. (about a week or so) I've loaded sjphone (voIP) software on it and hope to use it with my wifi, (the connection was choppy, and yes, I've have tried the same program using my HP IPAQ 4150 and ran fine). Now, I must admit, that before my HP IPAQ PockPC was not used that often cause I really did not like the idea of having a phone and a pda in my pocket all the time. but because the O2 XDA IIi has both features, I find it much more convient. My 2 cent... if you don't need wifi, go for the XDA2 Mini cause it is much more smaller. But if you are like me and want to have the latest and greatest and all the wizband.... then this unit is worth a look. To be honest, it all really depends on the software you load on the unit to make it slow. I will give it a thumbs up even if I had initial issues with it. Oh, like all Pocket Pc.. you really have to charge it all the time if you like to turn it on and off and use it all the time. The battery does run out quickly, so invest in a sync cable for your work pc so you can charge it while you are in the office. Also invest in a car adaptor so you can charge it while you are driving. Don't take me wrong, the phone does last you a few days on standby! talk time varies between 1 to 3 hours... why, because I have the screen on bright when I first got it... so to save on battery life.... reduce the brightless and also to black out the screen after a minute of inactivites.. turn the wifi feature of if you don't need it. Bluetooth is fine.... but if you don't need the use if it at all, turn it off.