Cheers, yeah, the Guides are terrible, had them on my MTB, tried them for trials in an emergency, it was scary as hell. Codes might be slightly better though. Formula I've had some really bad experiences with in the past, with two sets of their T1/The One brakes. Fine for regular MTB, but when I put them on my trials bike, they instantly started leaking past the caliper seals. Both sets, so I'm hard pressed it's just bad luck, has put me off them for good.
Was thinking the same, basically the only thing that's holding me back. Especially with those pics of broken Shimano calipers in mind... Maybe I should try and find some of those TRP levers and match them with the Magura calipers.