In relation to the APS or standard MCC: I did the MCC/JOC myself and was lucky enough to sit in on APS/MCC also for free as they were short a partner. I have been looking at the briefing pack for the assessment, and the APS to me seems only beneficial for the actual type rating. Was told by a captain that the idea of the APS is to make the type rating easier but it is marketed towards the assessment.
Everything in the assessment is covered in detail in the MCC section of the APS/MCC, the only difference i found between the MCC/JOC and the APS/MCC is that you do a lot of LOFT exercises and cold and dark setup etc on the APS, but it is great for the extra hours and familiarity with the procedures etc.
Having done both if i was to chose myself, i would probably go for the APS, purely for the extra hours and familiarisation with the aircraft, assuming you go on to a type rating, in terms of purely for an assessment, i cant see the big advantage over an MCC/JOC and some good preperation beforehand in a SIM close to the time.