Ended up taking delivery of an S3 Frontier yesterday morning. Bought it off ebay with some valentines money from missus and a stack of nectar points!
I have to admit I am very surprised by Tizen. The S3 navigates fluidly through its apps and screens and I've enjoyed my time with the device since. I am using the MD81 watch face right now. I purchased a Greatfine 22mm Silicone watch strap off amazon and am equally as pleased (not a fan of the stock strap). My 6P isn't enjoying the Bluetooth experience though - The samsung software (really nice UI wise) on a non-android phone requires the core Gear app and a few plugins, that are seemingly taking its toll on my battery. It is definitely draining faster than normal anyway.
Either way I am very pleased with the purchase thus far. Looking ahead, my main concern is with the battery life as these watches obviously have a pansy sized battery that WILL degrade fast. The frontier seems easy enough to replace the battery on though going by various YT vids out there.