As far as an all in one unit, the argument, as always, comes down to what you're going to do with it.
The Alesis QS6.1 is also in the price range of the XP-10, but has more advanced programming capabilities.
Depending on you home studio setup, your sampling could be taken care of with software.
Another option would be to get a nice controller (StudioLogic and Fatar make excellent controllers for the price)
and go for modules. In many cases the rack version of a synth can be several hundred dollars cheaper than the full unit.