I'm like Tim - I always thought the design of OE was good but could hardly ever get it to actually work.
Back is the early days I was part of a project that tried to make a commercial product (the Psion Netbook) on top of OE - which produced a lot of new recipies for OE and some very good work, but ultimately didn't deliver enough to avoid getting canned after the first million or so was spent.
I've spent the last few years seeing how possible it is to make embedded distros out of Debian and mostly learned that anything that strays far from the upstream involves a monstrous amount of maintenance, that package policy is what really defines a distro, and that only reliable mechanism and tested stuff has any longevity and reliability.
I do still like binary-based distros (Like Debian/Ubuntu) for many applications, over source-based ones like OE, but if you want significant divergence from upstream's policy then only source-based will do, and it's a much easier way to bootstrap a new arch than doing it in Debian. I haven't quite yet worked out where Yocto fits in the landscape of tools and distros, but I shall watch with interest.