Porti radar can be a run gunners dream a well placed radar can keep half the map locked down so you can run off and do your thing plus the radar acts like a beacon to your team and you can pretty much guarantee a couple of the randoms your with will stay close to it bringing in the enemy.

Also instead of flash banging corners you can get the same result without warning people you're on the way.

But yeah most people do seem to just sit on it.

Pretty much. I don't know any actual spawn points, but if I'm playing, I'm thinking, "Well, my teammates all ran to the A flag, so the enemies are going to spawn by the C flag.."

There's rare occasions where they'll spawn in your spawn, (which I've noticed mostly on Dome) but it doesn't happen that often to me.

While it helps to know the spawn points, it's not necessary if you use common sense.

Nah. People just call the PM-9 the worst submachine gun because of it's average damage, high recoil, and average magazine. I like the PM-9, though. It's like the UZI of Black Ops.  Good at hip fiiring.