I just finished fermenting a 10 gallon batch of ESB, split the wort in half and pitched WLP002 English ale yeast in one carboy, and WLP023 Burton Ale Yeast in the other.
The first thing I can tell you is that WLP002 is a cleaner yeast that drops right out of solution very easily. The Burton Ale yeast is also pretty clean and flocculant, but not like the WLP002.
The WLP002 contributes more flavor to the beer, it seems to give more malt flavor to the beer because it doesn't blend with the maltiness at all--it's giving very subtle fruit flavors that show the maltiness of the beer by contrasting it. The Burton Ale yeast tastes like it blends with, and adds depth to, the malt flavors in the beer--so overall it's like it muddies up the whole malt profile of the beer. Burton Ale Yeast also lets you taste the alcohol in the beer. My batch with WLP023 has a strong alcohol taste, the WLP002 almost completely masks the alcohol flavor in the beer.
You must read this post
http://morebeer.com/phpBB2/viewtopic.php?t=14317. I have had some strange behavior from the WLP023, although I don't think that it has produced any off-flavors in my beers. Also, these beers are still green. I think that the Burton Ale Yeast batch will do alot better with a few weeks of conditioning, whereas the WLP002 tastes very good after a few days in the keg.
I will definitely use the Burton Ale Yeast again, but I think that I will simplify the grain bill before I do. Also, I want to see how it turns out after a few weeks conditioning in the keg. I would also like to know how it does with a porter. It seems to me like it's just perfect for porter.