It's nowhere that simple. a straight six is likely to be sweeter and smoother than a V6 arrangement. An in-line six cylinder engine is geometrically balanced.
Lot's of V6's have been built around a 90 degree bank to bank profile; basically a V8 with two cylinders lopped off.
Valves are valves and camshafts are camshafts.
A 16v four cylinder in line motor can have just one overhead camshaft. Usually there are two, hence DOHC, twin-cam etc.
A V6 24 valve (four valves per cylinder) unit has two banks of three cylinders each cylinder having four valves. Commonly you'll find two pairs of camshafts. So, it's 4 cam engine.
Old V6's, such as Ford's Cologne V6 had a single camshaft mounted in the engine block - it operated the (twelve, in this case) valves via pushrods.
THe Rolls-Royce 6750cc V8 used the same mechanisms well into the mid 1990's.
Five cylinder units are unusual, quirky and fun. Audi started this lark in the 1970's with the Audi 100 5E. 2144cc unit, five in a line injector fed engine - arranged front to back but driving front wheels through a transaxle that turned drive through 90 degrees.
Not to be outdone by Fiat and Volvo, VW introduced (around 199
a V5, which is a kind of V engine with a very narrow angle between cylinder banks. Much like the earlier VR6 narrow angle V6's these used offset cylinders to shorten the block, but have much more in common with in line motors.
W's are stranger. It seems VW is leading the way with all these strange arrangements.
A W12 is kind of like a 3 four cylinder units moulded together, thus making the engine much shorter than a traditional V12.
Downside is, as always, weight. Waynne will thank me for not mentioning diesels.
V6 / Straight Six 
Linear Mode
