I am not really a big fan of these type of posts, but it kind of customary for one to come up once a game has been completed.
Actually, I would like to take a moment to discourage anyone who is actually attempting the endurance test of 5000 rank kills. If I had any sense at all, I wouldn't have attempted myself.
In my opinion, this achievement is completely unneccessary and has no place in an XBLA achievement set (right up there with Bejeweled's endless mode). Anyways, if you are a Xbox live arcade nut and hardcore completionist like myself, then by all means give it a shot, but there are funner games out there in which one could better spend his or her time.
On a side note, there was plenty of boosting involved in obtaining this achievement. However, out of courtesy to the BSG contest, I was sure to steer clear of the singles Deathmatches.