One thing that make make a difference for your best bitter Lennie, is recipe formulation. If you think it is better after 17 days than you can wait, but it is possible that tweaking the recipe can improve the taste of it very young. Do you use a lot of yeast, or a normal amount? 1.5-2x is pretty important I think.
Drew, was MB's stout on nitro?
I make half batches so I usually pitch pretty generously, but I'll try really socking the yeast in and see if that makes a difference. I'm playing with the West Yorkshire strain right now, its not super fast but a nice attenuative strain. I was a big S04 fan when it was $2/ packet.
My last bitter was TF Maris Otter 90% and 0% Simpsons 37L crystal, First Gold hops to 25 IBU, 1.046/1.012. It was bottled and is pretty tasty.