My personal grievances are using a laptop with ubuntu. No wireless casting of display to tv, no good smart phone as a mouse/keyboard control, the screen is sometimes sideways for no reason.
But Linux and stuff is interesting still. I'm just not ready for it as a daily driver.
KDE connecting infuriates the hell out of me. It's so close to being good. The features aren't at parity between the different platforms. It is absolutely awful at finding and pairing your phone. I have three different networks I connect to on a regular basis. I don't want to run static IPs on every network nor do all the clients support static IP. If you do use static IPs you better only need that one because it can't choose from a list. Wanted to scan a different subnet than you're on for your mobile device tough luck. I want to use it, I have it installed. I've said it IGMP hints. It's just not written well.
All that said, if you have an ISP bog standard router and one network that plays nice with it, it definitely works as a keyboard and mouse remote...