johnnydoom
firesticks are programable so it should never not be compatible. My son has reprogrammed ours a few times to make it better. The only thing that can become an issue are space requirements. Since, Storage on them can be an issue and affect performance so cleaning cache and deleting unwanted apps etc will help as will keeping programs up to date. Like any device , bloatware and unbeeded items get bundled so disable or remove them
As long as the source has high quality and the device has the capability to do high def...the quality as with all plug and play will be quite fine however as with any video, audio signal the more handshakes there are the more issues can arise and they can lead to lesser quality.
Nothing beats a direct source for quality so in most cases ethernet input directly into the tv and using the tv's app will be better than any stream or plug and play that is attached....but the difference will not be noticeable in many cases. Some tv's need the app updated for them to work correctly. As is commonly known, a direct hardwired attachment will always produce better reliability and quality...ie ethernet to tv ( with Netflix) or device will be always be better than running from wifi.
I have several devices that that I use to run Netflix and other online apps, internet music etc including a laptop, Oppo95, Macintosh music server, ps3, amazon firestick, ....and previously had a Wii U which we sold .....chromecast and Roku but dumped these as too unreliable. The amazon firestick is far superior to the latter two IMO. It is the only wireless device i use to stream to a tv. It replaced the Roku which didn't last long
My daughter uses the chromecast at University when they want to watch it on the big screen bs laptop, and a friend put the Roku stick in his cottage.