I'm a bit late to the party on this one, sorry
However, as said, it depends what you're into. The standard F1 is a great knife, good all rounder; but the F1x is a better knife in all respects. Sure, for arctic bare hand use exposed cold steel isn't the best, plus it's a bit too much of a compromise design to excel in any single application, but for balance sheer strength and competence in multi disciplined application the F1x has few contenders in its price range, when quality of build is taken into account, yeah, you could buy 20 cheapies for the asking price and why not, thats valid too.
The TK 2 is a great knife, a better knife a superior knife, way better than any F1 version out of the box for sleekness ease of application and finesse, I have one in my fishing bag and have dressed countless fish, have dressed and butchered medium sized game with it, but it ships with the volume of steel most of the Fallkniven knife range would be holding after 20 years of continual hard use. Fine if you're an old codger, but of more limited life span for the younger folk looking at longer term use.
The standard TK2 is a near spent stub in comparison to the standard F1, despite being the superior handling knife out of the box. The F1 will become the TK2 over an extended time period through use. However a full tang TK2 version will cost near three times the of the price of the F1x, and a F1x is a full tang knife a third of the cost of any alternative full tang version of the F1. It's more knife for less money and despite the steel it'll become a better knife over time through use. That in my book makes it a winner, not even Toddy could break it.
Then there's Fieldcrafter UK of this here parish, looking at and holding the F1x I tip my hat to that lad, he was head and shoulders ahead of the curve, he was producing a very similar carbon version of the modern F1x 5 years before we saw anything comparable by any manufacturer.... Just saying.