Definitely Swift. But:
1) If you plan to develop a SDK/lib compatible with both Obj-C and Swift and don't want to adapt to new Swift changes coming forward
or
2) You absolutely can't stand SourceKit related bugs in XCode happening now and then.
then consider Obj-C.
Would go pretty far to use Swift over Obj-C anyway, so I can deal with both 1) and 2) and still use Swift. It will just get better, so probably best to go Swift sooner than later.
then consider Obj-C.
Would go pretty far to use Swift over Obj-C anyway, so I can deal with both 1) and 2) and still use Swift. It will just get better, so probably best to go Swift sooner than later.