In my experience, front ported speakers are somewhat less demanding in room placement, owing to the port facing into the large area of the room. The caveat with that is that port noise (if there is any) will be directed right at the listening position. Rear ported speakers should have less audible port noise, as the port faces away from the listening position. The caveat is that distance to the rear wall becomes more critical as the port may "overload" the bass if too close. I would assume that group delay may also be somewhat worse with a rear port, but I am unsure how audible group delay is at bass frequencies in any case.