I know the bowyer in question, I know his views and consider him a friend - so I'm going to make a couple of comments here to bring the discussion back to a proper context because to quote him as saying 'yew is rubbish' without some background which I'm sure he provided is unfair.
The truth is actually already in the thread for anybody that bothers to read it and draw sensible conclusions.
1) Yew is a softwood
2)It can delaminate along the grain
3)Badger has only made 2 yew bows he'd really rather have kept.
That says it all really because none of it is consistent with making great long lasting bows. Historically we know this to have been the case too - from the sheer numbers of staves imported to England per annum for a relatively small bow using population and from the resupply needs of armies even after short campaigns. High draw weight high performance yew bows never lasted all that long.
Why do some think that high draw weight yew bows do last more than a season or two? Because most people who own these things are incapable of using them properly. Instead of working the bow, the bow is working them - what a surprise that the thing outlasts those archers. Put a self yew bow in the hands of an archer who can really wring it by the neck, and it generally chrysals very quickly indeed. There really is only one Archer of whom this can truly be said with heavy bows in the UK and that is of course Simon Stanley. Yes, he has owned the odd yew bow which lasted a long time, but by and large they don't survive in his company for too long which is why he uses them for special occasions only.
Whats the problem with yew? It isn't great at resisting shear - too soft and too poorly interlocked between the rings. Sap is good in tension, heartwood is good in compression,its light and can therefore be very quick - but it isn't great at resisting the sheer forces which you inevitably get, particularly the bigger you build these things and that is a real achilles heel. This is why it prospers better as a core wood with a hickory back and osage belly - that makes a really good bow - or as thin laminates in flatbows.
Yew is of course a beautiful wood and has huge emotional appeal when it gets turned into a bow. Not only that, but anyone who is seriously interested in archery history cannot take themselves seriously unless they own a yew bow. But lets not confuse emotion and a historical perspective with the hard facts of materials science.
Chris