I love them both, both are quality. But I do prefer Wyeast simply for, 3711 and 3725, oh and Roselare. Oh and pacman yeast.
I appears a lot of people here do not make starters. Either you are under pitching or pitching many vials or packs. I've done both, and yeast starters kill pitching straight from the manufactures package. Yeast starters are easy to make, vastly expand your yeast count, produce healthier yeast and cut your yeast cost in at least half. There is no comparison. I think White Labs and wyeast both make a great product.
Why does making a starter cut your yeast cost in half? After reading this thread, I almost hate to say this, but I just open the WL vial and dump it in my fermentor. Seems to work so far. I assumed you were supposed to do the same thing with the smack packs (after smacking of course).
If it's 1.06 or less you don't NEED a starter. You won't notice a difference in flavor with a small starter.
Now for a lager I do a 1 gal starter.