IP Phone With DECT Handset (That is handset, not headset)

A client I talked to yesterday pointed out this Mitel IP phone that includes a DECT handset. Seems like an interesting idea. I am kind of wondering if the handset is oddly heavy and bulky considering it needs to have a battery, dect radio and all in it? Does the handset charge when setting in the phone?

I'd like to hear your input if you use one of these.

Here is a link:
http://www.ipphones.co.uk/products.php?product=Mitel-Cordless-Handset-(with-DECT-Module)