Buy Kens HoverflyPro, you wont regret it. I love my 2 boards and they dont give me any problems at all. Incredibly easy to set up and they fly beautifully. For simple basic flying you have just 1 gain setting to set and the latest firmware from Hoverfly is the best they have done. the boards are fantastic to fly. Its been about 6 months now since Ken last flew his HFP and a lot has happened in that 6 months. Hoverfly have changed their method of dealing with issues or problems and the new RMA system works very well. You have constant support on their forum and a bunch of very helpful users.
I think Ken has the green board and if you do buy it make sure you get a line filter for it. The newer black boards have a built in line filter but thats the only difference, they have the same hardware and run the same firmware.
This evening I dusted off the box containing the H/F Pro board, took it out, updated to the latest firmware, did all the necessary calibrations, and installed it on my testbed quad frame. I did 3 flights under the street lights with the LEDs on all four arms providing plenty of light to see the quad and follow the orientation.
First observation, it seems a little less steady in full manual mode than I remember it to be, used to almost be better in manual than it was in autolevel.
Second observation, autolevel is still quirky, it had significant drift the first time I tuned it on so I used trim to get it steady, landed and did the save the trim routine then took off again, as soon as I engaged autolevel it took off in FFF, had to switch off autolevel. Landed, disarmed, and powered off and then retrimmed the TX back to center on all controls and powered it up again, took off, turned on autolevel and it held fairly well with only a little bit of drift.
Third observation, I turned on altitude hold and while it is significantly better than before it still isn't anything close to any other A/H I have or have used. It takes WAY too long for it to respond to changes in throttle position and finding the proper throttle setting where it wants to hold an altitude is just as aggravating as it was before, only difference is it doesn't do 10 foot altitude changes at random now. Once you do manage to find the proper throttle setting it seems to stay put for the most part but it takes far too much fussing around to get it to equilibrium, especially in light of MK and DJI only needing the throttle stick moved to center and it stays at altitude. OK, maybe only the DJI does and the MK tends to bob up and down a bit, but either one is better at altitude hold and it takes a lot less work to use it.
At the end of the first set of batteries I came back inside and swapped over to a fully charged set and went back outside. Took off and flew around a bit in manual and then flipped the switch for autolevel, it leaned to the right rear and started in that direction at a moderate speed, had to hold almost full opposite control on the right stick to stop it while I flipped the autolevel switch off. Next I tried something I used to do to get autolevel to work, I landed, disarmed, rearmed, and took off again, flipped the switch for autolevel and it worked almost as well as it did on the first flight with only minor amounts of drift requiring slight control inputs to get it back to fully level again, not much has changed there I see. Flew it around for about 8 minutes and landed, back inside to let it cool off a bit and swap to the last set of charged batteries.
Back out again, took off, turn on autolevel, watch it want to fly off in a random direction, land, disarm, rearm, take off and autolevel is back to some semblance of normality, shouldn't have to do that to get it to work though. Flew the remainder of the packs switching between manual, autolevel, and autolevel with altitude hold.
Final impression, for roughly 2X the cost I have a flight controller that works as almost well as either of the DJI Naza I have and not even close to what either of my Wookong-M can do. While it's nice to see things have improved a lot since I last flew it, I am disappointed that over a year and a half down the line there are still issues with basic functions like autoleveling and altitude hold. I'll keep the board on the frame for a while and try it out in more challenging conditions than dead calm air and 70 degrees ambient temperature, I don't expect much difference from my prior experiences though.
Ken