So the new MVM map, Bigrock, is really awesome. I sincerely hope this is a permanent addition to the mode rather than a temporary event like Caliginous Caper was.
The new robot Engineers are real pains in the ass, always spawning in secluded spots away from the action so they have time to set up, possessing two or three times the health of a normal engie, and have lightning fast build times for their sentries and teleporters. While the sentries are annoying, the teleporters are lethal in that they move up the spawn point and seemingly speed up how fast things spawn rapidly. They only seem to have the weakness in that they have a glowing pillar that appears to make themselves conspicuous when they spawn. Needless to say these guys need to be taken down as soon as possible. I love'em.
On a spur of the moment, I got some of my friends and Kinseti to tackle the new map, and we roll right over the normal difficulty Bigrock mission, then try advanced. We get our asses thoroughly kicked, only reaching the second wave, before doing the normal one again. In fairness, my three friends that were there with me don't take TF2 very seriously, so they're kind of doomed on any difficulty above intermediate.
So in the time since it's been released, I've done the normal Bigrock mission four times (pyro, spy, spy, huntsman sniper) and the map is great. The three items that were released look really interesting, I even got to see a Vaccinator Medic on our team. I'll definitely need to see more of them in action.