I've been having a few problems with the household Chromecast (Gen 1), in that it buffers after playing for a while, for no apparent reason. This is on iPlayer, Netflix and Prime, so not service specific. My hub stats are all healthy, BQM indicates nothing exceptional, wifi quality is excellent (TP Link mesh system). So for a rare change I'm not blaming Virgin Media. I'm not interested in conventional pay TV choices including VM or Sky, so I'm toying with the idea of replacing the Chromecast with something different, perhaps a Roku.
I have purchased both a Roku Express and an Amazon Fire TV stick, only reason why I sent back the Roku was that live streaming on the 2018 US Open Tennis didn't work. Apart from that both worked well, it just depends on which apps you need. It's worth noting that you need a good WiFi signal and the Roku Express only connected at 2.4GHz whereas the Fire TV connects at both 2.4GHz and 5GHz.
The roku 4k (streaming stick +) has 5ghz wifi and has tv power and volume controls on the remote, and voice search. Worth the extra over the premiere and HD ones IMHO
Roku plus points are it has the widest selection of apps - it has now tv, apple tv as well as all the others. Also the voice search for films/shows is good as it shows all apps with that film. Although it knows if you're subscribed to prime or netflix, it's not smart enough to know about individual purchases in your library eg rakuten or play movies
Roku minus point is wifi only, as they don't work with a usb lan adaptor like chromecast and firestick (strictly speaking they do, but that removes the smart aerial)