you've got most of the important points to do this form of heating, the running costs are sightly more than traditional radiator system, I personally think the benefits out weigh this issue.
1. comfort if you like a lovely toasty warm house ufh
2. control if you would like to set accurately the temp of each individual room ufh
3. design if you don't want any restrictions on where to put furniture/lockers ufh
the beauty of ufh is it runs at low temp which suits the modern condensing oil/gas boilers also to future proof you system leave a duct from the ufh manifold to outside the house (4" sewer pipe) should the technology of electric or geothermal heating improve or become cost effective you can be connected up without much hassle