Join Date: Mar 2002
Location: California Central Coast
Less difference than you'd think
I once wrote an article demythologizing the differences between the two, but it ran to, like, 1000 words, so I'll just give you the Cliff Notes version.
There's a lot less inherent difference between twins and fours than you might think. In fact, practically none of the difference between a particular V-twin and a particular inline four has to do with engine layout. Rather, power characteristics are determined by the myriad other decisions made by the engineer. Displacement, cylinder dimensions, intake and exhaust tract geometry, carburetion, valve sizes, and camshaft timing all affect an engine's personality. Engine design isn't a one-dimensional problem, and understanding engine behavior is a lot more complicated than counting cylinders.
With the variety of powerplants available today, you can get the power delivery you like in almost any configuration you like. If you want the pavement-ripping thrust of Big Torque, you can get 70, 80, or even 90 lb-ft in either a twin or a four. If you prefer an intoxicating rush of peak power approaching a five-digit redline, you have the same choice. Take some time to look at the dyno charts and read the road tests, and don't prejudge a bike based on engine configuration.