I agree with you Downunder, except in the case of my V-twin Harley-Davidson. lol.
Actually, I have the new Twin Cam 88B engine, with the two counter balance shafts and its a very smooth running engine. It's a very ingenious setup. You maybe able to come across it at their web site if your interested?
For those who are not familiar with the Harley V-Twin. The connecting rods share the same crankpin and vibration is what they're all about, thats if your into that kinda thing? The Ladies sure seem to like it!

Happy Fly'n....