I've found that the Tunebot is more user-friendly than iDrumTune.
On both, when you play the drum, there's two similar behaviours: 1. You have to tap the drum loud enough for the device/app to register the hit. 2. It takes a second or two for it to analyze the sound and display the result. The Tunebot has a red light that comes on when it registers the drum, and tuns off when it finishes its calculations and displays a result. So you know you hit the drum with the right intensity, and you know the device is working. It's easier to develop a consistent stroke that the Tunebot will recognize, and thus easier to get consistent results from the Tunebot. iDrumTune doesn't give any indicator that it heard you hit the drum, or that it's processing the result. So you hit the drum, you wait, and maybe you hit it hard enough, and maybe you didn't. No way to know. So you waste time analyzing the tuner and not the drum.
Secondly, the Tunebot has the filter button, and iDrumTune doesn't. Both devices have to sift through the myriad of different tones and overtones that the drum makes. So sometimes when you tap the drum, both the Tunebot and iDrumTune will display different notes depending on which overtone it registered most strongly on that tap of the drum. So you'll be tuning a tom, and one tap gives 100 Hz, and another gives 150 Hz, since it picked up different sets of overtones on each tap. But on the Tunebot, if you hit the Filter button, it displays the overtone that's closest to the filtered note. So tap the drum, get 100 Hz, hit Filter, and it will only display notes in that ballpark of 100 Hz. It works very well in practice. With iDrumTune, I don't get nearly as consistent results, as I sometimes have to tap the drum a few times to get the one overtone I'm targeting, which makes it harder to use.
As for a few thoughts on the Drum Dial, it still has use even with a Tunebot or iDrumTune. When doing head changes or when dealing with a massively out-of-tune head, I think it is a little faster to use a DD to even out the drumhead and then tune the drum with the tuner. The electronic solutions are less perfect filtering through a crazy mismash of overtones on a completely unevenly tuned head.