well, i used to really like them when i didn't know much more about them than their nice paint work.
in recent years i realised (and i'm talking about the steel stuff here) that they weren't actually THAT special. even more recently some things on them have been pointed out to me that makes them even less special to me.
for example, i have 2 terry dolan cougars, lovely bikes both of them and they are both custom, but lugged custom, meaning the lugs are bought in, the tubes are cut and the frame is built, so other than the differing lengths of the tubes they are no different to the standard sizes, so in essence it's the least custom you can get if that makes sense.
but the lugs are generic or cinelli or whatever so to a certain extent they are not that special and i now see a similar thing with colnago, their lugs are effectively standard but with their logo in it so in my opinion they are no more special than most other steel frames of similar pedigree.
for the record, i like them, but i don't think they are any better than for example my cougar bikes. good quality, well made but by todays custom frame builders standards not as special as i used to consider them to be.