I was curious and tried out the Coldstar Commander. It was a 4 person team game at 500pts each - Tau and Necron vs Eldar and Grey Knights.
The GKs stayed in reserve... I mean, they STAYED until they auto came in, which really made the game lopsided. The Eldar had cover behind buildings and used a Fire Prism to go after stuff, but they didn't have a chance.
My Coldstar Commander swooped up and nailed a Guardian Squad, running it off the board. He then swooped behind the Fire Prism and took it out with his High Output Burst Cannon (too close for missiles, he switched to guns
). Then he swooped to the other Guardian Squad but they made their leadership check and stayed put. Only after all of this did the GKs show up, but after failing to hit my jinking Devilfish, we decided to call the game. My commander could have just went back to gliding and gunned down the remaining Guardians and the Farseerer, but we figured at that point it was just too painful to play out.
This was only really possible because at the low points, no one had flyers or skyfire. I did put a shield generator and stims on the commander in case someone got a lucky shot off, but even then it was a pretty one sided example.
I think there are some things that the Coldstar might be ok at (like swooping behind tanks for rear armor shots/placing a banana in their tail pipe), but the cost along with lack of customization and squishiness (1 wound while swooping could equal death!), I don't think it's overall worth it.
Fun maybe, but 1 flyer, skyfire weapon, or lucky lasgun is going to drop a lot of points out of the sky.