Ok, I can definitely comment on this, although I think my experience is pretty uncommon. My previous MTD 535-24 had an ash neck that looked fabulous, but was not that stable or adjustable for low action. (In fact, it needed a refret, to stop buzzing!) I had it checked out by a number of reputable luthiers and their opinion was that the neck was not very strong front-to-back, as it had been slab-cut and had lots of grain irregularities and weak areas. Looking at the back of the neck, it had lots of lovely oval-shaped grain patterns, but not a lot of straight grain running from body to headstock. I've since bought another ash/ash MTD with mostly straight grain-lines and it's far more stable and the same luthiers have given it the big thumbs up as far as wood-strength goes.
Cheers,
EG