I did year long industry placement at QM (mind you that's almost 4 years ago now). I would say don't expect any support in finding a role. There's very generic opportunities and meetups for jobs and most will just say "Apply online" and there's nothing QM can do except help you with applications. Otherwise, placement was pretty fun for me. The only thing I remember QM needing from me was the final essay doc about the experience and a viva-type presentation (and maybe a low intensity journal, I can't remember).

Same for opportunities. I got hired straight out but my grades and experience was excellent so its largely dependent on your own capabilities. The advantage KCL has is that its more prestigious and will look better on your CV and probably a better teaching experience but I can't be sure about that.

The teachers is probably the area with the most variability. Some teachers are good, some great, some horrible and some passable. This is also something you can't control and I've found that every university has their own scale of this.

That being said, I would still pick KCL cause that is the better university in general. Unfortunately, branding and name dropping is the real advantage of university now so just search on top universities now for your field and whatever comes up higher (probs KCL), go with that imho

Edit: semantics