I am somewhat surprised at the loyalty of A9 users. I have used the A9 and Optima receivers since the original A9 was first sold. I have had unexplained crashes in the past, but not lately, suspected local cell phone system interference with A9 and other systems, but unproven. My only real complaint was with the clarity and completeness of A9 user's manual and instructions provided with receivers and 2.4 GHz modules. I had particular problems with getting 3-position flaps to work properly in my scale electric powered models. I finally got trimmable 3-position flaps working on two servos with slowed servo action, I also had confusion and problems with the "scan" vs "normal" modes and awkward binding procedures. A recent transmitter software update via the HP-22 PC interface device has prevented further accidental scan/normal mode problems when binding or range checking a new receiver. All that said, I have been well satisfied with Hitec support service and personal help from techs by phone and e-mail. BTW, I like using the SPC port connection to give "brownout proof" power to Optima receivers and separate power to servos via the speed control's BEC or separate switch mode BEC.I like watching in- flight motor battery voltage via the SPC setup. I did manage to "fry" a receiver by plugging the SPC cable in reversed polarity working in poor light without my glasses. I don't like that my A9 has no "model match" feature which is a patented Specktrum feature . Lack of this feature allows any of my models with battery mistakenly left connected to respond to my A9 transmitter and start up in the pits. Not a problem with IC models though. By the time repair support from Hitec is no longer available, I may no longer be around, I just turned 80. BTW, I built my first vacuum tube RC system in the late 50's