I like both the VIIB and C but I would personally switch to a VIIC later in the war when radar detection and other upgrades becomes vital (if VIIB can't get it?).
@Penelope_Grey
What upgrades is needed to make the VIIC go 8 knots submerged? As far as I remember my early war VIIC's have only been able to reach 7 knots on batteries.:hmm: