As long as it is a fully weighted controller..you will get a similar (although not QUITE the same) result as your X8...
But apart from the Fatar branded (or alternatively branded with their company Studiologic) fully weighted keybeds, most (controller) keybeds are sub-par in my view.
The best I have played on (when compared to a real acoustic) is the VMK series from Fatar with the Grand Touch action. These have been superseded now with later models with apparently an even BETTER feel...but I personally have the VMK 176+ which is the 76 note version, still with the Grand Touch and fully weighted, but it is about the length of a PA3xPro 76 and actually weighs LESS!!!...means I can fit it in the car!!!!
M-Audio and the Yamaha XK series controller actions are okay at best, and the Akai 88 controller is absolutely awful!!!
Again, I am talking weighted actions...Be aware that standard controller keybeds - 61, 76 or 88 notes - will give about the same feel for piano work as the PSR series!!!
Mind you the trade-off is that the weighted beds are really not suitable for organ patches or synth patches....this is why I compromise at gigs with the PA3 (or the G70 would be just as good) you get a premium semi-weighted keybed action, which when you get used to it is quite nice for piano parts, but you get the action speed to get the organ and synth parts happening as well....