Dr. Betotte is still the metronome that I use the most. The newest additions to this app are a native iPad version and syncing of all settings using iCloud.
The features that are most helpful to me in practicing are:
• Adjustable volume sliders on: quarter, 8th, 16th, triplet and downbeat sounds.
• Tap tempo
• Savable tempo settings.
• Coaching functions to gradually move the tempo up and down.
• Syncing
Features included that I don’t use that often are:
• Halftime feel
• Adjustable swing feel functions
• Multi beat mode (Change where the strong beat occurs.)
• Playlist modes (Practice with multiple time signatures.)
• Quiet count (Drop metronome beats.)
• Creating your own metronome sounds
• Visual metronome choices (Count, Pendulum, or flash the screen.)
• Pitch generator
• Timer
The adjustable volume sliders act just like those on the well known, Dr. Beat metronomes.
Dr. Betotte iPad in Landscape
There is no way that this can get as loud as that big old warhorse device, Dr. Beat, no matter what sound you choose to use. However, you can easily use a dock or a wireless speaker setup to get as loud as you’d like.
The savable tempo settings were there from the first edition but now you can use iCloud to sync the settings. (Might want to back up before you turn this on, just in case.) The other thing to note here is that all of the settings are synced. Change the iPhone to a lurid orange which looks fun and you’ll get blinded by it when you turn on the metronome on your iPad.
Volume controls on iPhone
An eyeful of orange on the iPad!
I love to be able to quickly get the metronome going and jump right in to some of my standard practice routines. There are a few oddities to the playlists however. First, it acts a bit weird because it feels like you are going out of that setting when you hit the playlist button. You aren’t. You are going back to the choices for that playlist.
Awkward but you get used to it.
Playlist detail on iPhone.
Tapping back brings you back to the Playlist screen.
Second, even though it always seems to change the rhythms correctly, it doesn’t always switch to the tempo. Often, whatever tempo you had going is going to stay the tempo. Even with that, it still allows you to stay in the zone because the tempo will then be the only thing that you need to change.
By far, one of my favorite things to use is the coach functions. There are three. Gradual up/down and the Step up/down (essentially the same thing) and Quiet Count. I don’t tend to use the quiet count that often but it’s a great way to test yourself if you are having any trouble keeping a steady tempo. I love having the Gradual and Step settings. Even though the concept is the same, it’s nice to have two of them so that you don’t have to reset them as often when practicing passages that have different lengths and tempi. Using this, you can set an upper and lower tempo limit. Great to use this when trying to raise the speed of a difficult passage. Or conversely, to work towards a slow tempo. Start at the tempo where you can breathe the phrase that you want to hear and work your way down to the tempo that you want the piece to be at. (Tchaikovsky VI opening for example.) I’ll forever be grateful to the low horn player that shared that practice tip with me.
Coach section on iPad
Halftime is another fun way to practice a difficult passage. I’ll often do something that I call doubles. I will play a passage very slowly, say at 40 bpm and then directly after that play it at 80 bpm and then down to 42, up to 84 etc. Halftime helps me do this with a little less metronome fiddling. (Admittedly, I most often practice doubles using the Cycles metronome app.) Sadly no longer available in the app store.
One of the things that I really like about the iPhone version of this metronome is that when you turn it landscape, you get a nice big face and still have access to various settings. This is great when you only have one hand free. Easy to reach over and use the slider to change the tempo. In this screen, you have access to everything that you need including the various note sliders.
The metronome view on the iPad always shows playlists. Not a big deal in landscape. A bit awkward in portrait. There are preferences to hide certain looks depending on the orientation but not for the playlist section. I tend to always use landscape if I’m using the iPad version so that doesn’t really bother me.
The playlist doesn’t go away.
Dr. Betotte is now a plus app on version is 3.5.
It’s compatible with iPhone, iPod touch, and iPad and requires iOS 5.1 or later.
It costs $9.99 from the iTunes store.
Keep in mind that developers need to eat and you can’t buy a Dr. Beat for $10. It’s worth the money for me. I highly recommend this metronome.
If you want to try before buying, there is a free version to try that is an iPhone native. It does not have all the bells and whistles.
Get it here.
There is also a version for your Mac that you can get directly from the developer, Seishu Murakami’s website: S’s Works Software. This version includes a sequencer but you have to practice with your computer.
I first wrote about this app in July of 2012: Dr. Betotte version 3.2.
practiceapps 
dead link in last paragraph:
Since that first Dr. Betotte post, I have found a great rhythm programming metronome. If you want to read about that one, go here.
Sorry about that. Thanks for the heads up. The app in question is sadly no longer in the app store. The one that is still available that I like is covered here: https://practiceapps.wordpress.com/2015/04/21/tempo-advance-metronome/