I just bought Arion for a discounted price as a Fryrender customer
Arion use all GPU and CPU's of your hardware (hybrid)
It deliver unbiased results or,if you want,you can save rendering-time switching to -draft-mode( a faster solution close to unbiased)
I use it preparing my scene in C4D R10.5 with my Fryrender plug-in to export the scene in that format then open it in Arion,so i can't say how it works importing directly Obj files
you can choose what video card will work for computation and how many cores of Cpu will work too,leaving some free hardware's power to modify your scene if you want
If you think to do an heavy-use of it you must have two videocards,like i told in my previous thread(an high number of CUDA cores and at least 1Gb video memory)
If you are a Max or Xsi user you also have LIVE plug-ins and animation
...sadly Randomcontrol have decided to "kill" all others export plug-ins(C4D-SKP-MODO-RHINO-MAYA)..and Fryrender too !
anyway i'm an- unbiased rendering- supporter,so my suggestion is choose one of them