My experience with the Chromecast was pretty much the opposite of yours.
I acquired one, plugged it in, installed the app on the phone and configured it. About 6 minutes in total, and it works well with a good picture. I use it for the on demand TV channels, Netflix, Lightbox and Plex. Apart from the god-awful interface on the latest android Plex client, it all works smoothly and well. In fact, it works so well I bought 2 more, for the bedroom and spare room TVs. $89 on sale from Leemings, which I didn't think was outrageous for a 4K capable streaming device. Works well off controlled off my phone, tablet or laptop.
I got the Ultra so I could wire it in (using powerline adapaters as per @Hiro's excellent suggestion above), and be a bit future-proofed in terms of 4K etc. Also, I got some google home speakers, and it is kind of cool to be able to select, plan and pause content using voice commands instead of a remote. I just say "Hey Google, Pause" in the living room if, for example, I'm watching something and the phone rings. Personally, I would buy them again.
Also, if you have a PC lying around, it's worth putting Plex (or Emby or Jellyfin) and a decent-sized hard-drive or three on it. They you can rip all your Blu Rays and DVDs etc, watch them on any networked TV, and not worry about finding/shuffling optical disks again.