Phone is fine - menu system is easy to use - and easy to setup. It is certainly much better than the the RTX 3088 phone. Both my 3088 phones died after about 18 months - there seems to be a known speaker problem - no fix.
So I upgraded to the 4088 phone - BE WARNED - you need to buy both the phone and the base station. A 4088 phone is NOT compatible with a 3088 base station.
Call quality, reliability all seems fine at the moment - Jan 2013. If there are issues or problems I will update this review.