There are already quite a few DJ sequencer apps available in the iTunes store, and the folks at BuzzyTeam have jumped into the foray with one of their own called EasyMix (US$2.99). Just as the app's title suggests, everything within it is easy to do, and not at all at the expense of quality.
When starting off, there are five basic styles to choose from: Techno, Trance, Progressive House, Breaks and Disco House, along with some specialized styles based on members of the Loopmasters team. Some of these are more obvious than others as far as how you're hoping your finished product will sound. For example, I had no freakin' idea who this Tai Jason guy was except that, by his photo within the app, I thought he was Vanilla Ice at first. Yeah, I guess I'm sorta old.
Once within the sequencer itself, it's extremely easy to get started (there's that "easy" word again). There are five track mixers with four samples for each track, and you can just start selecting them at will. Touch another sample within that track, and it queues up and switches for the next loop. Keep some tracks turned off and turn them back on if and when you want. There are also sliders beside each track for its volume, along with three equalizer sliders that affect the entire loop. If you still want more ease in your EasyMix, just hit the random mode button and the app will pick the samples for you.
A very nice feature of EasyMix is the ability to no only record your loops, but play them back from the device and download them from any computer. Select the "transfer" item from the main menu and the app serves as a mini web server if you're on a WLAN. Browse to the address the app tells you to and voila, there are your tracks in WAV format for download.
The sound really needs to be heard through headphones or external speakers to be appreciated. The loops themselves are higher quality 44.1kHz, 16 bit, which is definitely adequate enough and won't at all scream that the tracks were generated in something inferior.
There's not a whole lot one can say is bad or wrong about EasyMix.The app has a brief few help screens to get you started, though it could be more informative in what exactly those three equalizer sliders do. You can play around with them yourself and get some idea of what they do, but sometimes it's all guesswork. I would also like to see the option to automatically fade in and out of the entire track, in order to make a more complete, exportable song I'd want to share with friends.
One glaring issue EasyMix has is not having the ability to change the tempo of the track, though I guess if they start adding features to this thing, it might have to be called "Not-So-EasyMix" soon enough.
If you're big into DJ loop making apps, you already know what you need and want. However, if you're just looking to play around with some cool beats you made yourself, though not necessarily with samples you found or made yourself, EasyMix is worth looking into.
Here's an EasyMix YouTube video demo.