The R10 is a 1.6 crop sensor camera. The 15-30 has a full frame equivalency of 24-48mm on the R10. An 11-22 will have an equivalency of 17-35mm.
If the 11-22 is anything like the EF version, it will be a very expensive lens that displays minimal distortion on a full-frame body. If you are using a crop sensor body, you will be paying a premium for optical qualities that are going to be cropped out by the smaller sensor. The 15-30 is a stop faster than the EF 11-24, which is likely to be at least $600 more expensive.
So, ask yourself if having a 17mm wide angle is worth the extra expense when compared to a 24mm (equivalent) lens that is far less costly.
Alternatively, you can pick up a 2.8 Tokina 11-20 in EF-S mount and use an adapter for a fraction of the cost of either lens.