I agree, the A3 amp is a better amp then the X-A2 but the X-RAY is almost identical to the A3 CD player, it has the same DAC and transport.
X-A1 & X-A2 does not have remote, on the X-A-100R & X-A200R. You can see a little circle next to the tape loop button, that's the remote sensor. Also, I think the X-A2 looks better, coz it has a blue light rathe then the red (personal preference).
And as to the A3 being better, the reason is mainly that the A3 is a dual mono deisgn, both channel is completely separated. And it has a little more power (85W), but a newer version just came out (you can tell by the gold trim) and it has 100W per channel. Here's a picture of the X-A100R and X-A2. X-A1 looks identical apart from the remote sensor.
For both, you can bi-amp or use it as a pre-amp with a X-AS100 dual mon power amp later.
Notice the separate powercord for each channel? The A3 power amp have the same design.
For more information, go to www.musical-fidelity.co.uk
you can download the manual for all their products on there, have a look at the X-A1 while you are there.