Draytek Vigor range is quality kit, at still reasonable prices.
The advantage of the 2100V would be that it's all in one box, which means 
you get QoS,
and it will let you make calls either via the VoIP or normal land line, so 
you only need one phone and yes you can use DECT phone.
Considering the sipura prices it would be reasonable choice.
Regards,
Martin
(my 2600We hasn't missed a bit in over two years,  now 2600VGi as well for 
VoIP)