Trying to decide on this Quest it seems if you do side with the Gangers that they don't actualy take over the town.. as in taking over shops and services. So is this just a big way to kick yourself in the butt for vendors and doctors?

I usally play nutral/good so might be the wrong person to reply but I did not see an advantage to me in siding with the gngers...

Powder Gang has their own doctor.

In the prison, mind you. Killing Doc Mitchell erases all medical help from Goodsprings - it's really only good for Chet now (the [censored] coward).

Does the Powder Gang doctor die at the end of the NCR attack on the prison if you don't help them fight?

I didn't help them fight but left after doing their other quests, they stayed alive as the buildings never get cleared.
The NCR don't seem to actually start attacking the main building until you enter it, and the other two only contain gangers.
I found this out coming back after some weeks, the Idolized NCR attacked me on site and so did the remaining gangers when I entered the buildings.

Buggy.

I encountered the same thing - I entered the admin building after the attack, and the whole NCR strike force was gathered in the front room, blasting me the second I entered. Needless to say, I retreated out the door as soon as I could. I wonder if anyone survived? Not that I care - Powder Gangers are scum. I was only taking advantage of them.

So you lose Doc Mitchel?
Do you lose Chet and Trudy also?