I had the second version of this lens (18-135 IS STM) for a short period with a 70D and it was okay, but I never got along with it all that well. When I bought my 80D a while back, I got a great deal including this lens (18-135 IS USM NANO) as the kit. And for anyone looking to buy an 80D, just go ahead and get it in a kit with this lens. It's a good one.
I work in a Communications Office in local government so I cover a lot of events (press releases, ribbon cuttings, council meetings, picnics, employee functions, festivals, live performances, etc.) and I need something flexible for both stills and video that will give me a fairly broad zoom range while still maintaining excellent image quality.
This lens is just a really happy medium.
Things I like:
Quick Focus: This lens focuses very quickly and very quietly. I can't imagine needing anything faster than this for any kind of work. This lens and the 80D feel like they were made for one another. In video mode, focus is silky smooth and dead silent. In stills mode, it's interesting in that it sort of "snaps" into focus rather than gradually getting there or "sliding" into focus. A real treat coming from the first generation micro-motor and second generation STM (which was pretty good).
Zoom Range: This lens covers a range of about 28-200 or so. Good enough for my needs as it allows me to get groups or rooms in an image while also letting me zoom in to isolate a subject (like the mayor giving a speech or a special guest sitting at a table). I can sort of stay out of the way better than if I were using something like an 18-55 or 24-70 on full frame. If they had given us this as a 15-135, I'd be in hog heaven as I do wish for something a TAD wider sometimes.
Image Quality: A variable aperture "kit" lens shouldn't be this good. Maybe I got a good copy or just got lucky or whatever, but this baby is a joy. I've used it for several events with excellent results and I've also used it around the house and yard for photographing my daughter. Colors are excellent, sharpness is excellent even wide open (especially at the longer focal lengths), contrast is good (this is an easy fix anyway).
Stabilization: The IS on this lens is phenomenal in stills and video. Does what it's supposed to do and doesn't leave me wanting for anything in that regard.
Things I don't like:
Lens Hood: I don't get it, but for whatever reason Canon still insists on not providing users with a lens hood. For the retail price of this lens, it sucks they don't include it. Thankfully, the folks at Vello offer one at a significantly lower price point that's just as good.
Variable Aperture: I'd rather have f/4 throughout than f/3.5–5.6. Or give me f/2.8 to f/4, even at a slightly increased size.
Zooming: I wish this were internal like the Sony 18-105 f/4 G lens, which is far and way my most favorite APS-C "normal zoom" lens for any system, period. If Canon could give me that exact lens for the 80D or EF-M mount, I'd probably just die. For the record, I'm fine that it doesn't offer electronic zooming as I'm not a fan of that and the PZ adapter can be added if need be for that functionality, albeit at a higher price and larger kit.
All-in-all, I'd say this lens is a keeper. For brighter events, outdoors, family picnics, zoos, etc., this guy is a treat. If you're indoors a lot or shooting low light, you might want something like the 17-55 f/2.8 IS but it won't be as quiet in video and won't give you nearly as much reach.