Hmm...
My current game has four 14th/15th level Eberron characters, all of who had DMG wealth when created (except the VoP guy), including my new PC (as my follower of the Flame died heroicly in combat a few weeks ago). I'm not sure exactly where theys stand relative to DMG wealth; it feels like my new guy has more stuff, but it may be that he's just got fewer, better items and less cash on hand. Stats were best of 3 sets of 4d6 drop lowest rolls.
So while as individual characters, yours are probbably more powerful, I think having a fourth, combined with a higher average level, probably makes it a wash. We're higher level, but you've got 5 PCs, and a lot more specials going on, so your guys are stronger. Not overwhelmingly, though, I think.
My current game has four 14th/15th level Eberron characters, all of who had DMG wealth when created (except the VoP guy), including my new PC (as my follower of the Flame died heroicly in combat a few weeks ago). I'm not sure exactly where theys stand relative to DMG wealth; it feels like my new guy has more stuff, but it may be that he's just got fewer, better items and less cash on hand. Stats were best of 3 sets of 4d6 drop lowest rolls.