I purchased a vane type AOA, a CYA-100, when the inventor was first starting out, at considerably less than the $625 price at Aircraft Spruce:

http://www.aircraftspruce.com/catalo.../aoacya100.php

It consists of a balanced carbon fiber vane on a short aerodynamic strut, turning a rotary hall effect sensor.

http://sensing.honeywell.com/product...sition-sensors

and a row of LED lights for a display. Set points are adjustable.

It works very nicely on my Husky, being especially useful for very short off field work where minimal energy is needed and short final is at or below 1.1 Vso. Also good when down in a steep Idaho canyon, loaded to the hilt with camping gear, flying close to the canyon wall, and needing to to a sharp turn to drop over some tall trees into a short back country strip. Sure, you can do it seat of the pants, maybe, but the AOA is very reassuring, letting you know what the margin is while cranking and banking down low when all one's senses are on edge. I like it.

Don't feel the need for one on my glider. Maybe 3 MKIV yaw strings. !!!Conflict of Interest Alert!!!

bumper
MKIV & QV