I had the weather flow with the ballistic arc app. Suited me just fine for a few years. I’ve since then gotten a 5700 Elite, and it is super handy having it all in one unit and not having to juggle a meter and the phone. Once you learn the interface it really does streamline some things. However, if you’re not competing you might not reap the benefits quite as much. If you have all the other useful gear though and have the $ burning a hole in your pocket then I’d say go for it, but if there is any other shooting stuff you want to upgrade, or even take a class somewhere, you might see that dollar go a little further.
Especially if you’re shooting at the same ranges most of the time. Once you get out there and realize the kestrel is telling you the same data as your current setup, you might wonder what you spent the money on. Especially if you could use a nicer scope, bipod, new barrel, reloading supplies, etc.
But of course they are super handy and now that I have one I wouldn’t want to not have it!