For some time now, I've been experiencing severe braking judder on my ST4s - it's taken a while, but I finally got it sorted. I'd had the head bearings changed before Christmas, to little effect - they were rusted badly worn, but not completely shagged – but would only have lasted another few thousand miles. After that, I was looking at the fork slider bushes and the disks themselves – neither cheap options.
Snell's then got in touch with Ducati UK, who suggested trying the modified banjo assembly for the brake master cylinder that Ducati produced to address similar problems with some Multistradas. So we did, it was fitted this morning and all is now smooth as silk.
So, for anyone suffering from that dreaded judder under braking, one solution (YMMV) is a simple banjo kit! It's listed as a Multistrada part, number 69922861A. In my case, it was supplied and fitted under warranty, despite the bike being 18 months outside the warranty period. Very impressed with both Snell's and Ducati UK.