Actually, most of the greats hybrid pick for arpeggios. It enables them to get the great even sound of 'alternate' picking combined with the efficient motion of sweep picking.

It's not a matter of one versus the other, it's more a matter of combining them in a meaningful way.

I remember walking into Berklee thinking, like Al Di Meola, if it isn't alternate picked it isn't worth it. But, I was soon introduced into the fabulous technique of economy picking.

--Bottom Line--

If you want to get quick and want to be able to execute your lightning speed licks without any effort whatsoever---learn to economy pick. In case you don't already know what that is, it's just alternate picking, but when you switch strings your first pick attack goes in the direction of your own motion, thus eliminating the wasted motions alternate picking brings.

For example, alternate picking going up a scale looks like this((3 notes per string)):
DUDUDUDU....

Economy Picking would look like this:
DUDDUDDU...


At first you will find economy picking does not sound quite the same as alternate picking, and it doesn't at first. When you get the hang of it, however, you can't really tell the difference between the two---save one's far easier.