My trike was ready on Friday (upgrade from Large to XL) so I went to the "not so LBS" to pick it up. I rode it around campus on Friday and had a blast except for one big no no! Having a foot slip off can be dangerous. If it hits the ground, you can run over your own leg. It happened to me, but I managed to lift my leg before it was sucked under the frame--mild sprain that didn't keep me off of it yesterday.
2 7 or so mile rides later, and I can report: It's damn fun! It handles well, but I can tell that it's not hard to imagine flipping it at speed. Body english is important in high speed turns.
Speed is still tough to judge, the PlanetBike 8.0 computer is going totally erratic on me. I've aligned the magnet to one of the sensor heads, adjusted the distance to magnet, pulled out hair, etc. When I get over 16 mph, the readings will start to oscillate to a low speed, then a high speed, and all over the place. Of course, it's a 35 mile drive to the trike bike shop, and I'm just trying to work it out myself.