vBulletin definitely has more features - but you can pay for the extra code with slower loading pages.
IF you start thinking really seriously about moving to vB, it might be worth setting up a vB on a test server, then seeing if you can find someone who can rip out a lot of extraneous code you don't want or need, so as to streamline it. I've certainly seen other big vBulletins running streamlined code.
vB really does offer so much control, though - phpbb is simple and sleek, but simply cannot at all offer anywhere near the same amount of control. I was pretty astonished at how little there is in the phpbb admin panel.
Customising vBulletin isn't so much of an issue - the basic template layout is simply 2 HTML files within the admin panel, plus editing of the CSS in a somewhat more powerful way than in phpbb. There are more advanced editing options in the admin panel for modifying the template, but it's all still very much HTML based, rather than messing with lots of different phpbb files for their template.
If you ever look to move to vB and need a hand then I'd be happy to help out and try and help you with some of the features. Ask how busy I am first, though.
