Don't go cryin to Bell if you can't work the rotors with something else but the RADS and want warranty support. RADS works best for all of the 4 bladed Bells hands down over the others. You get what you pay for...
There is another new player in the field called IAC, their model is called the 1087 and is priced near the RADS and VXP. They also make the vibe portion of the new 412 onboard monitoring system (BHVM) that Bell/AAI recently STC'ed.
Regards,
Chuck