what do u mean u will daisy chain your X10D with the PSU and X-ACT? If its just for power, then yes get the XPSU so that both your X-ACT and X10D can be connected to the XPSU.
I have not heard X-ACT but I still use my X-DAC for my HDCD collection and Wadia dock and found that the sound coming from my previous budget Marantz CDP CD6000, it did improve and gave more life to my set up. But with a more mid end CDP, it does not serve much purpose except for decoding HDCD. So, if my X-DAC is having similar technology as the X-ACT, it may give a different sound to your system.