Is your 18-135 great or 'just OK'

I have the USM version which came with my 80d. I was pleasantly surprised by it, the focal range is very useful for a walkaround lens and it's great for video.

If you aren't interested in video there are probably better ways to spend the money, but getting it as a kit lens was a no brainer for me.

This is my main lens for the 7D Mark II, when using flash in the studio. For solo models, with a 1.6x FoVCF, one generally doesn’t need less than ≈︎35mm, but it is nice that more is available, if the model has a hairpiece, or wings, etc. On the telephoto end, having up to 135mm upper range is great for face and tighter shots. The lens is pretty sharp, and while obviously not L build quality, it’s fairly robust when treated reasonably gently. I would not use the telephoto end for a portrait lens, because you will not get much background blur in most studio situations — a faster lens, zoom or prime, is needed for that. Stopping down to f/8 improves many things in IQ over the variable f/stop at wide-open. For this application works well, and an excellent value.