Without doubt The OD of this kind. I hear the H&K Tubeman is a toy in comparison, I once did try the Vox Big Ben, but then I had a close encounter with the TD... The one I have was made with the Tube Works logo and by reputation supposed to be the ugly duckling, but even so I couldn't be happier.
One shouldn't confuse the TD type of ODs with the Tubescreamer type of ODs. TDs make everything fatter and more compressed in a powerful way. TSs gives you a bluesy shimmer.