With both the EH Black Finger and the Damage Control Liquid Blues pedals I have been experimenting with different tubes. For both boxes, replacing the right tube with a 5751 really smooths out the response, etc. The Groove Tube 5751M is pretty good for a new tube, but a NOS 5 Star 5751 is even better (especially in the Liquid Blues!)
By using a 5751 in the Liquid Blues, it solves one of my complaints: the "Nuclear" footswitch on the right adds too much gain to the pedal. With a 5751 in there I can live with the gain boost, and it keeps things from getting too raspy, to boot.
The EH Black Finger is a lot of fun- you can select between a lamp and a LED for the tube opto-compressor. There is no tone control so you have to experiment with different tubes to get the sound that you want. (I haven't even looked inside but for a retail price of $300 they ought to have a few trim pots inside for fine-tuning the sound.)
Funny thing is that both of these pedals sort of give a Dumblesque sound to your rig- I think it has something to do with the tube compressor stages... And FWIW it has been suggested that the Trainwreck designs have a lot of similarities to the LA2A tube compressor.
I was almost thinking of bringing the Liquid Blues back to exchange it for the more expensive Womanizer, but with the new tubes I put in it (including a GT12AX7M on the left side) I'm having too much fun to bring it back... (With two GT12AX7M's in there it was just too raspy! )