I like to run Kingsford competition in my UDS... more even, less ash, and I get higher temps than blue (for a given amount of air) or it runs great at low temps. Kingsford blue is on sale a lot more often and easier to find, so I have a bunch of it. I like the low ash level of lump, but I have ended up with variable temps so I don't trust it for long cooks or when I can't/won't babysit it.
UDS, 30 Year Old Kettle, I need to build something bigger. KCBS CBJ