"The iRig Pro I/O is a solid ‘workhorse’ iOS accessory, offering an audio input that’s suitable for both instruments and mics (with phantom power available) as well as MIDI In and Out for sending and receiving control messages. There’s a headphones port, too, which means you can monitor your input even on newer iPhones that lack their own output."
+ Combines audio and MIDI interfacing
+ Separate headphones out with level control
+ Comes bundled with plenty of free software
Following closely behind is iRig Keys I/O 49, the fourth entry in the round-up and the best iOS keyboard:
"The IK iRig Keys I/O 49 is small enough to find a space on even the most hectic of studio desks, and is equipped to handle basic recording duties and general purpose MIDI control on stage and in the studio. As a package, it’s comparatively good value, too, particularly taking into account the impressive bundle of desktop software that comes free with it."
+ For MIDI control and audio I/O in one
+ Mac, PC and iOS compatibility
+ Impressive bundled software
+ Tablet stand included