Most surprisingly, Apple added Audiobus support to Garageband. I have a few pieces in progress using this. The only drawback is I keep finding the sounds I want in GBs native instruments and have to look for excuses to record other apps!
Arturia has updated the iMini to include Audiobus as well which is a pleasant surprise. I have been using it in Tabletop quite a bit but Tabletop doesn't support polyphony with the iMini. This is going to be one of my go-to synths on the iPad since I've been using its "big brother" on the desktop for years.
Auria too has had a few updates addressing some serious bugs and adding some usability features. As of this writing, Auria is still a bit flakey with Audiobus though. With nothing but source and target apps running, I still see Auria crash during audiobus recording frequently. Hopefully the latest release reduces that.
On a more serious note, BeatMaker 2, which was becoming my favored Audiobus target has fallen out of favor with me. During a glitch while trying to move one project, BeatMaker 2 managed to delete my entire recording folder which in turn makes several of my songs have broken links. The way BeatMaker handles files is, in my opinion, asinine. For the time being, its off my usage list - there are far too many other alternatives that don't corrupt my entire library. I recommend and realize that more frequent backups are a good idea! In my case, it had been a few months since I backed up the iPad so the BM 2 songs were lost. C'est la vie! By the way, for those of you who HATE iPad sandboxing, this is why its there. One buggy app will not corrupt the storage of other apps - that's a very good thing.
I also spent a little time creating in just the Korg apps - iMS-20 and iPolySix just because its so fun to do! These apps do support Audiobus but I did everything in the app for these pieces since they integrate so well with Soundcloud.
Lastly, to mellow out a bit after a stressful few weeks of media barrages, I put together a soft jazz piece on Logic9 with the EWI. A bit quick and rough at the moment but it helped :)