Originally Posted by Graf Paper

Well, now I'm just merely confused instead of uncertain. lol

So the biggest differences between the VIIB and VIIC is as follows:

VIIB - Faster surface and subsurface speeds and longer endurance submerged.

VIIC - More durable and greater maximum dive depth with marginally quicker dive times.

At least this is what I've gathered so far from everybody's replies so far.

Having more options for future upgrades, especially radar, sonar, and anything else that helps to increase your advantage would definitely tip matters in favor of the VIIC....unless those same options are also available for the VIIB. I could really care less about deck/flak guns as I try never to put my boat in a position where using them is needed except for finishing off a merchant you don't want to waste any more torpedoes with just to sink them.