The thing that sets Lemur apart from the other MIDI control surface apps is the scripting engine. You can program a variety of functions in these scripts. BlueSkyRepublik's OPAL-MS is a patch designed specifically for the Teenage Engineering OP-1, which lets you do a lot of interesting things, without having to write the scripts yourself!
I have launched the OPAL-MS app, OP1 and Lemur Modulation Suite. This is a Liine Lemur App programmed for the iPad and Teenage Engineering OP-1 Synth. Feel free to download from my Youtube Channel Page and try (requires iPad, Liine Lemur and Op-1). Please comment for questions and feedback.