Oh great, I have a MicroX which is the little sister of the X50 and very similar. This one has like the X50 an edit software which can be used standalone and as VSTi in Cubase. That is very comfortable because all your settings will be stored with your project and you can automate a lot of parameters.
It is very important to know that the usb connection delivers midi data only and you have to use the audio outs and an audio interface to record the sound of the X50.
You can use it multitimbral because every timbre uses an own channel - same as with any multitimbral VSTi.