What sort of budget? Formula’s Oro is cheap now- old design but very effective, and pretty damn cheap. Just a wee bit heavy is all.. I’ve just replaced a set of mine with a pair of The Ones, which are the best brakes I’ve ever used, but they don’t make the Oros look bad.
Did I mention that Formula The Ones are the best brakes I’ve ever used? Light enough for XC racey bikes, powerful enough for DH bikes… Bags of feel and progression too. Not entirely sure I’d consider them good value, considering that there are brakes that work extremely well for a fraction of the price, but if you’ve got money to spend then I’d spend it here. Or possible the R1s but they’re a less all-round useful brake, more XC/trail oriented IMO.
All fully servicable, parts available from CRC, excellent support IME from Formula…