I have a Magic Module in one slot and an Aston 1.05 in the other and no problems there. I have not tried a Matrix Reloaded so I cannot really say but I would think it will be OK. I am thinking of replacing my MM with a Dragon cam soon. Or maybe I will wait for the ultra cam to come out.
I used to have a problem with my 5100 hanging sometimes especially when channel hopping but since I downloaded the most recent software for the 5100 from the Humax site the problem has stopped. Its been a long time since Humax released any new software for it - I dont think they bother with the older receivers.