I’ve used GNOME in the past but currently use KDE Plasma. Both are good, but as for recommendations most Linux people I know of say for new users that if you’re coming from Windows start with Plasma and if you’re coming from Mac OS start with GNOME since those are the closer desktops to what you used before and will make things a bit easier. Depending on the distro you choose you may also have access to other desktops like Cinnamon, which I haven’t used but have heard is even easier than Plasma for new users coming from Windows. It’s not ready for daily use yet, but the upcoming Cosmic desktop may also be quite good for that.
Combination of software availability and the perception that Linux is only for developers/servers and you have to be a computer genius to use it. Even if you can convince someone that just running Linux isn’t rocket science, there’s still commonly used software like the Adobe suite and MS Office that just don’t have feature-parity level alternatives, even if those alternatives are almost there. I can do most of the stuff I used to do at work on LibreOffice compared to MS Office, but not everything. And while compatibility with the MS Office file types has really improved leaps and bounds over time, there’s still some noticeable issues when opening those documents with one program after making changes with the other. People mention Photoshop a lot as a deal-breaker, but especially with GIMP 3.0 coming, GIMP will be a lot closer to Photoshop than most Linux PDF editors are to Acrobat. The only one I can find that has even close to Acrobat’s features is Master PDF Editor, a piece of paid software (if you want all those features without an annoying watermark) that I don’t think the free version of is in many repos. People say to use LibreOffice Draw, but that’s drawing software meant for entirely different file types and is really not good for any PDF with any type of formatting in it because Draw isn’t designed to handle it. I don’t need those features on my own home PC, so I’ve been running Linux on my personal machines since 2009, but for those who do need those things, it might be a hard sell.