If you want GPS/altitude control the Skookum SK-720 Black edition should be on the list too. I'd give the Align APS a wide berth though. It's very obsolete technology by modern standards and I've read a few horror stories as well as seen first hand a big Trex 800 camera ship fall out of the sky for no apparent reason while using one (and not for the first time according to the owner). Also as i understand it it has to be used with Align's obsolete '3GX' FBL which itself is quite troublesome and no longer available anyway.
For the most part GPS systems dont appeal much to heli flyers because for the majority of us the fun is to be had by actually flying the heli. GPS systems are all about fully autonomous flight which is really missing the whole point of heli flying for most people. Different story if you want the heli to perform camera work or long rangd FPV or such like, but that's generally more the multirotor part of the hobby.