So, I'd thought I'd stop by my local store to see when these would be coming in...and to my surprise, they already had some! Long story short, I walked out with one. I do not have any experience with the 10-22, although I do have the 11-22 for the EOS M (and the 16-35 2.8 for FF).
- The one thing that jumped out at me immediately is how LIGHT this thing is...definitely easy on the arms - balances well on the SL1, too. Great size for traveling.
- Unlike the 16-35 (and 10-22, I believe), but similar to the 11-22, this is NOT an internal zooming lens...the barrel is slightly extended at 10mm, retracts into the body until about 15mm and then extends again SLIGHTLY until 18mm. It barely extends out, though - probably a centimeter at most.
- This has the "STM" focusing mechanism just like all of Canon's newer entry-level lenses...mainly optimized for video. It is virtually silent in a normal environment (in a super-quiet room, you CAN hear a faint, high-pitched whine as the lens focuses).
- The filter size is 67mm, and the front thread (?) does not rotate when focusing.
- For those that have the M + adapter: there is a noticeable difference in FOV between 11mm and 10mm (this lens can go wider), and this lens is light enough so this could be another UWA option to consider.
So, overall thoughts...
- Light, compact, easy for travel
- Very good center sharpness throughout the range
- IS works well (I was able to get keepers down to 1/4...for those using it with a 70D or larger camera you can likely do better)
- Very affordable at $300, and very high price/performance ratio
- Some edge/corner softness observed, particularly at 10mm
- Purple fringing showed up in a few of my shots (wide end)
So...I think that this is a great lens for the money, although those looking for top UWA performance will want to look elsewhere (and likely will, anyway). Compared to the 11-22, I found the 10-18 to be softer near the corners...but that's more of a testament to how outstanding the 11-22 is, more so than a condemnation of the 10-18. Compared to the 16-35 on FF, the difference between center and corner sharpness seems less drastic on the 10-18. Unfortunately I cannot compare it to the 10-22, so I'll leave that one to someone else...
In the end, I wasn't blown away...then again, I didn't necessarily expect to be. But it is what it is - an entry-level/travel-sized UWA lens, and for $300, I'm not going to complain too much. It is plenty good enough for vacation snapshots and casual shooting. I can be pretty demanding when it comes to IQ, anyway.