I had a FireStick Lite and it was great. Everything works well. Even some of the non-FireOS Android apps will work in the FireStick Lite. I thought the FireStick 4K would be better since it supported 4K resolution and was the flagship model for the FireStick until the 4K Max version came out. Anyway, I started to notice some really frustrating oddities with the FireStick 4K: 1) Silk Browser (same version as in my FireStick Lite) does not show images and icons properly, especially for video frames where the video controls at the bottom are non-existent when you hover over the video panel with the mouse cursor from the Silk Browser. There may be tooltips that show up as you hover accidentally over the missing icons/images. These show up on the FireStick Lite. Other webpages where there are icons on the buttons (for social media feeds) and sports team logos - they're either missing or displayed in truncated pixels.
2) Android mobile apps work in FireStick Lite absolutely won't work with FireStick 4K. A good example of this is the 10Fast VPN app. The screen is non-responsive in FireStick 4K and requires the Mouse Toggle app to make it somewhat functional to select a country. But even then, the app does not function properly. With FireStick Lite, the interface still suck as it is made for portrait mode but it is very functional.
3) I expected voice dictation to work when the search popup keyboard shows up if one needs to do a search and typing is so awkward. I think initially it did work until all the updates seemed to have broken that functionality. So, I did what the Amazon support says. I rebooted the FireStick, unpaired and re-paired the remote, logged out and logged back into my profile, and finally reloaded from factory multiple times. The voice dictation just isn't there.
I couldn't figure why these things aren't working for the FireStick 4K and it works for the FireStick Lite. So, I took inventory on the Silk Browser settings, versions, and then looked at the FireStick FireOS versioning. Bingo! The FireStick 4K OS is Android 7 with FireOS 6 while the FireStick Lite is Android 9 and FireOS 7! You would've thought that Amazon would have firmware updates to make their flagship FireStick to be in par with the Lite version but no - they're selling the 4K version for higher price and the OS version is inhibiting proper functioning than the Lite version which has a very slight downgrade in memory size and no 4K capability (which I don't need anyway since my TV only supports up to 1080p). So, I'm kind of disappointed that Amazon actually sells and advertises the 4K version to be better than the Lite version and costs more. I think everyone who bought this 4K version is duped with the lesser Android OS!