At least that is what it reminded me of.
Battery life is 12-14 hours of real work with the big battery (which costs something like 18$ more than the regular one).
I still use a Macbook Air for iOS development but I now boot the Thinkpad for everything else.
(Oh and if there's an engineer working for Spotify in the crowd, thanks for the Linux app!)
KDE is a bigger and more complex system so it works a bit differently depending on what distribution you use. Some distros like KDE Neon always have the most recent KDE while other like OpenSUSE Leap prefer to use stable versions of the applications.
When it comes to wifi/sound/etc it has to do with whether the driver for that contains binary blobs. Some distros don't ship blobs due to security and/or software freedom concerns while other distros have a more relaxed policy when it comes to proprietary software.
Thinkpads have a reputation for being very easy to run Linux on. You should expect everything to work out of the box. For the Dell computer you might have to install drivers separately but you can't tell for sure without knowing the exact model you have. You could do a test drive with a Live USB to check out. I wouldn't expect things to work out of the box on the macbook though. Apple isn't very Linux friendly and their macbooks have many specialized components that are only found on Apple products so Linux support is not very good. But even then, some dedicated hackers still try to reverse engineer them so you might have better support if you have an older model instead of the latest macbook.
The following table can help a bit with determining if wifi will work on your computer:
https://en.wikipedia.org/wiki/Comparison_of_open-source_wire...
That's what you want.
Just works, anyone can use it, and if you wish, you can right-click on anything and have tenthousand config options to make everything exactly as customized as you want it.
Edit: Fedora on workstaton / laptop, CentOS 7 on a dev server where a desktop has utility. Not on production boxes.
Which is why I use it!