I have tied the blood knot for years, using mono to mono. The uni-to-uni knot is a great dependable knot, but it takes time. The blood knot is much faster, when you get it wired, and can be just as dependable. I have had them break, but mostly on the old backing on my reel, and when that happens, I just re-tie it and actually add another wrap or two, wet it and sinch it down.

As far as a mono to braid, I use the uni-to-uni knot. The blood knot seems to slip alot with the mono to braid unless you add a few more wraps and then you end up with a huge long knot:)
JMO

CAM