As someone who owns a tadpole and has ridden several of them, you should know that they are not nearly equal in terms of handling capabilities. As far as the AB vs WW goes, I'd expect a slightly better deal with AB, though don't expect much in terms of service.

As another poster has recommended, you can pick up a used Catrike for the same price which is a better deal. BTW, that's what I did. The Greenspeeds, Trice, and Scorpions are great products, but they're probably out of your range. The Challenge is a work of art but it's very spendy.

Trikes are not as stable as they look because you can't lean the same way you can on a 2 wheeled bike. If you're looking at the WW lower end, that would be a Terratrike. They're definitely better than a Sun (which I have also test ridden), but once you get in the 25mph+ range, handling starts going south fast. This is the case with a number of trikes. Performance trikes which are designed for speed are going to generally give you better handling than the ones with a higher seating position.

When you test ride, get it going fast and you'll see what I mean. I've had my trike on 2 wheels many times and flipped it once. Having said that, trikes are an absolute blast to ride so I don't want to dissuade you -- I just came in from a ride on mine. All trikes handle well enough at low speeds, and they're great it stop and go traffic.