here's a review of the A2B by yours truly. i rode the bike yesterday (along with an electric scooter and a Ultra Motor Europa) at a local shop, Sound Speed Scooters. you can read these other reviews here: http://www.xanga.com/toshiclark/690499078/soundspeed-scooters/
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I had a chance to test ride the Ultra Motor A2B on January 24, 2009.
Commercially available electric bicycles are hobbled by laws that vary by state and province. Power limits of 250-750W are common as are speed limits of 20 mph or 30 km/h as appropriate in your country. Companies offering electric bikes thus have one hand tied behind their back, as it were.
With that in mind I wasn't expecting to be overly impressed with the A2B. After all, my homebrewed electric bicycle can do 23-26 mph on the flat as my one-bike production run is far too small to attract the attention from federal auditors. However, numbers aren't everything.
The A2B's construction and design are impressive. The battery is securely stored in the downtube. This is a great location for a battery being central and relatively low to the ground. The only downside of this layout is that the battery isn't designed to be easily removable on the road. As a result, the 72-73 lb bike can't be carried on buses' bike racks around Seattle, as they have a 55 lb weight limit.
Other aspects of the construction were also impressive: the rear dropouts have a built in indentation and bolt for the rear hub motor's torque arms, the headtube and stem have a slick-looking integrated design, and the fat 24 x 3" tires are covered by commuter-friendly fenders. Not as impressive was the funky rear rack: its side bars have to be 20 mm thick, far thicker than those on any normal rack. This isn't good because normal panniers won't fit.
Riding the A2B was very much unlike riding the Europa despite their similar specs. Although the A2B has a high front end like the Europa it felt completely different thanks to the suspension, frame geometry, and soft suspension. More than anything else it felt like a small, rear-heavy downhill bike with 20" wheels. I really liked how it handled and found myself slaloming obstacles down the street, jumping off of curbs, and trying (unsuccessfully) to bunnyhop it.
The small wheels really make the electric assist snappy. My personal electric bike has 26" wheels and a Crystalyte 407 hub motor powered by 48V of lithium. The A2B has 20" wheels and its hub motor runs off of 36V of lithium. Despite this seeming disadvantage the A2B absolutely smoked my bike off of the line all the way up to about 18 mph. At that speed my bike pulled away and continued to its supralegal speeds while the A2B cruised along at 20 mph. In case all this jargon isn't clear: the A2B accelerates quickly and feels very responsive.
Overall the A2B gets a big thumbs up from me. Is it perfect? No. But is it the best commercially available electric bike out there? I think that it is.
But I really was sad. 
