I have both and there are good and bad to both. For a novice, I think VB is easier but still difficult as I think there is just way too much. With IPB, a buyer seems to have to know a little more about coding and that is a pain in the rear. I haven't looked at my IPB site in ages because it's not active but I'll upgrade and see what it looks like.
As far as designers, IPB has some outstanding designers very willing to help when they can. When I was first thinking about purchasing IPB for the heck of it, a well known IPB designer set up a live board for me so I could check it out before I buy. Told me to keep it as long as I needed. I thought that was awsome.
I think tech support is much better for IPB and I'm so thankful I've found a great VBulletin hosting company with good tech support or I think I would have switched my live forum to IPB.
But as far as features, VB has it hands down, especially with social enhancements and add-ons.
Just a note from the peanut gallery
crap I ment to choose VB on the poll, mods change my vote to VB please. Gracias.