For tactical practices and trainings we (101.J) have been using CD much in part to the 1 life to live. With our size the matches and rounds are very invovling (averaging about 30 members playing), just as well we remove the time limit. However the con is this gametype is not concept, but rather the maps themselves. Attacker spawning too close to the defenders being a main fault I've seen on more then a couple maps. The maps objectives were made with the 3:30 timeframe in mind, but frankly to get the tactical gameplay you need to remove the timer, because as we have seen it, it becomes run to cap, and ignore the fire, that plain isn't tactical.
Going onward we have to drop it as a gamemode for us due to the maps. Looking at TE with limited tickets at this point, it unfortunately was what most of the maps has been designed for.