Big fan of Formula here…got RX1(RX Caliper/R1 lever) on my Zesty and RX on my wifes 575.
Superb brakes IMO. Came from Hope X2 previously and these are much nicer in a few ways. They're stupidly powerful (180F&R on my Zesty) and modulation is far superior, they seemingly only require a very light touch, if that makes sense. Pads are lasting forever but it has been very dry here in Bristol. They also look great, thats the most important thing obviously!
As the pads have worn i can't say i've noticed the lever travel increasing so they must auto-adjust.
I can't really comment on the long term as mine were new in early march and my wifes new in April so not really long term use yet. Our annual Alps trip will be the real test as we'll be riding them on the same trails we did last year using Hopes (X2 and Mono Mini).
I would recommend you buy the bleed kit too as you may need to shorten the hoses which might require a bleed through.
Hope that helps….Oh…and buy some now! UK Bike Store is cheapest although Evans will price match if you ring them.