Got a couple of pictures to illustrate what I've discovered so far. In the first photo, you can see a Grendel, Locust, and Warhammer. In the second are two Warrior Attack Helicopters.
The Grendel illustrates how well the Arkab Tan above Wolf Gray works. I really think this just needs a few details - some red lines, the cockpit, and weapon ports - to be finished.
The Locust also looks quite good, with just a coat of Bounty Hunter Green over St. Ives Green. Again, this just needs some details and it'll be table-ready. The Speedpaint effect isn't as obvious, but I should note that this miniature has been used for several painting experiments and its surface details are softer than usual.
The Warhammer is iffy. The Widow Black coat looks patchy, with some white holidays visible. I applied this with a smaller brush, and that might have been a mistake. Still, I think with some details and touch-ups it'll be acceptable for the table.
The two Warriors were given a coat of Steiner Blue, which is a Speedpaint 1.0 formulation. I let them dry for over 24 hours before starting to apply Muster Yellow. As you can see from the left-hand Warrior, the yellow is a little patchy and will need another coat, but it did not reactivate the Speedpaint medium. Not related to the Speedpaints, but before doing more painting on the Warriors I removed the rotors. They're in the way. Luckily, it was the work of just a moment with a razor blade to cut them free.
In general I'm impressed with the Speedpaints. If you just want to get some miniatures on the tabletop that look okay, you could do a lot worse. The biggest problem that I can see if that it's harder to touch up little mistakes. You might be just able to see a tiny spot of yellow on the left-hand Warrior's wing. I can't just paint it over with Steiner Blue; I'll need to first use some primer.