Yes, up to v7.5 there were major limitations on certain particle render types in the version of MR that shipped with Maya during those releases.
Such as no particle motion blur, to some particle types not rendering in MR at all.
Most of those limitations have now been eliminated as of v8 & 8.5.
Also, I have moved this thread to the correct forum, as I can better help you from there/here if needed.
Feel free to post any issues or questions you have and I'll help you as soon as I see your post
Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS