A few years ago it was announced that a 2-state symbol Turing machine was proven to be universal (http://en.wikipedia.org/wiki/Wolfram's_2-state_3-symbol_Turing_machine). However, Vaughn Pratt disputed the proof, and I gather he still disputes it. Wolfram's prize committee seems to be satisfied.
Is there anyone not on team Wolfram who believes the proof is correct?