Can't speak for the new models, but suspend/resume is bulletproof on the 9550, Mac-like experience installing Ubuntu

If you stick with non-bleeding edge distros, I think it will be fine. A colleague had some problems with Arch occasionally with newer kernels (especially when using Powertop since it often lags behind a bit). I've also had occasional problems with a very similarly built Toshiba laptop. By the time distros like Ubuntu were using those kernels, all of the problems were fixed. Probably in a 3 year period it only happened twice, so it wasn't a huge deal since I was expecting to have occasional problems.

I run Arch on a XPS 15, it was relatively painless and I have no major complaints, I am very cautious about upgrading the kernel and only do so periodically. I would 100% consider switching to something else if they manage to solve packages as Arch has.

Same with the 9360 and running Fedora.