Some more options...
CTRE Magnetic Encoder (absolute within one rotation and relative - we make this one)
These are unique in that it uses the same cabling as Talon SRX, so they plug right into the Talon.
http://www.ctr-electronics.com/srx-m...c-encoder.html
If you are using Versa, there is a slice with same CTRE sensor built in.
http://www.vexrobotics.com/vexpro/al.../217-5046.html
Another analog encoder (MA3 US digital) I've used and seen teams use (absolute within one rotation)
http://www.usdigital.com/products/en...tary/shaft/ma3
Another popular quadrature encoder(relative - us digital) I've used and seen teams use.
http://www.usdigital.com/products/e4p