I've built and painted the
Scourge part of the starter box, The Voivod did the
UCM faction of said box.
We went different routes, mostly because of the models themselves. I suppose I got the easy half, as the Scourge vehicles can be fit into their dropships without any additional wizardry; just slide your craft into the CD-rack and you're done.
I did mine with magnetized bases, since they're supposed to be skimmer type vehicles, but had they been tracked/wheeled/legged, I would not even have bothered with those.
My miniatures were spraypainted with an under/base coat of silver, which makes it a bit more durable than brush-on paint. And after the painting was done, I simply sealed them with some dullcote. As they are plastic (so more resistant to chipping), and have a strong base coat, that's all I deemed nessecary. I've not played many battles with them yet, but so far, they're holding up perfectly.
As for Voivod's UCM; he ran in a bit more challenges there. When you assemble the dropships and attach the peg mount underneath, you'll find that it basically blocks the middle position of the tanks. The APCs are fine (two per dropship), but for the the tanks, you'll need to get creative.
He didn't bother with mounting them, as it would have required magnets in the turrets, glueing the gun arms in a stowed position, and doing something wildly creative with the flight stand. So he deploys the tanks from the dropships as usual, but the dropships remain empty. He places one vehicle on the base of the dropship to show it's loaded up.
I find that this can be slightly confusing as an opponent, since it's not clear how many vehicles are actually loaded in the dropship and when deploying, a vehicle can start out on the dropship's base, creating additional confusion (was that tank embarked or on the ground now?). So when you go that route, I'd recommend using numbered counters, so everyone can see how many tanks (and of what type) have been loaded onto the dropship.
Should you want to go with the magnetized option (which I'd prefer), you will need to address the flightstand issue though. I was thinking of using a recurved wire attached to the tailpipes of the dropship and the base, so the space on the belly of the dropship can be used for the tanks and APCs. Of course you will have to model the magnets in the turrets as nicely as possible, since they're highly visible on top.
So, long story short; Scourge; easy as pie, just load them up and don't bother with the paintjobs as they're pretty resilient to abuse anyway. UCM; needs a bit of thought and creativity, as the models are not suited for out of the box mounting...