I have a little leather clad Jeantet billiard that I smoke Christmas Cheer in, that is just fantastic. I paid around $40 for it unsmoked. I am guessing that it was manufactured during the 60's, maybe 70's. Also, the stem work on the pipe is really sweet considering it is a factory pipe.
Having said that, leather clad pipes do have the potential to be putty babies. There could also be the potential for green wood which hasn't been aged properly, if the manufacturer was ethically challenged. I suppose the brand and era that the pipe was manufactured could be good indicators of quality.
Having said that, I have always been strangely drawn to these sub standard pipes. I suppose it is because they represent a bygone era, similar to art deco styled pipes.