I'm sort of leaning towards just guying the Applied Ballistics app now because that's what's in the Kestrel.
Kestrel sells an Elite 5700 with Hornady 4DoF also, if you preferred 4DoF.
Honestly, I just counted and I have 9 ballistic calculator apps on my phone, plus AB on my Kestrel. I use 4 of them regularly. I use Hornady almost any time I want to just run a quick BC trajectory calc, sometimes Ballistic AE for quick trajectory calcs instead, use StrelokPro for matches, use AB on my Kestrel at some matches and while hunting, use AB on my phone for some of my non-match rifles because I prefer using my phone but so I can stay in the same profile and same engine on either kestrel or phone.
I just started using GeoBallistics over the winter and actually kind of like it. I might go there instead of AB on my Kestrel for matches if/when StrelokPro falls away (hoping the sanctions are lifted before it fails).
The ones I don’t typically use are Nikon SpotOn, Shooter, Winchester Ballistics, and Bushnell Ballistics - I have them and have used them, and they work just fine, but I don’t use them.
The real trick to remember - they’re all based on the same, relatively simple math. Any differences are really inconsistencies in input: garbage in, garbage out. Good inputs for environmentals, good calibration (“truing”) of your BC, good muzzle velocity, and everything should come out nearly identical.
We also have to remember, and frankly, admit, that not all shooters have the skill nor own rifles capable of shooting small enough to true their waterline at distance within the margin of the apps, nor are they willing to miss enough shots to determine their actual waterline. One click of our scope is 2.6-3.6” at 1,000yrds, so when guys are sending 30” groups at a 10” gong at 1,000 off of a truck hood, it takes a LOT of shots to determine where the center of the group is really falling, and whether the app is wrong by more than 2 clicks, or the shooter simply can’t shoot small enough to determine where the group is centered.