I'm HAPPY HAPPY HAPPY with my S5! I don't have a problem with Touch Whiz. The UI is snappy, no lag. I love the camera (never thought I'd admit to being happy with a cell phone camera but it's more than adequate in a pinch). I haven't uninstalled all the fluff (maybe unnecessary but fun/cool) features. Just removed a few apps I'd never use. Runs like a champ. Having an issue with it coming on when it feels like it but hopefully I'll figure that out. Oh, no problems with BT to any other device, keyboard, or my Ford Flex. The text message feature in my car works too. Messages are on the nav screen and are read aloud. I'm almost afraid to update to 4.4.3 in fear it will break something!
Thanks for the comment. Yeah I would rather wait a bit before the update. That's what I did with my S3 so I missed the horrible 4.3 update and stayed on the smooth 4.1.2. Still a great ROM.