Quoted from Pinstein:
Finally found a pro with the help of a fellow pinsider. How do people feel about a shaker in it? Meh? or F Yeah?
My personal rule for adding a shaker motor to my games is to ask if a shaker motor enhances the game's theme and further brings you into the game's world when you play. So games like Earthshaker (obviously), Twister, etc.: Is there anything in the theme that might cause the ground and/or the surrounding area to shake/quake/rattle/rumble/vibrate? So WWF Royal Rumble counts - not because of the word "rumble" in its name but because stomping, bodyslams, etc. cause a wrestling ring to shake. Games where car engines are regularly revving and bombs are frequently exploding are some more great examples. I would also put a shaker motor in any Jurassic Park game because of approaching T-Rex's steps, etc.
So all of that said, I haven't put a shaker in my BKSOR (and likely won't) because I'm still not seeing many (if any) places where a shaking effect would make $100 worth of sense to me. It makes no sense to me (again: in my personal opinion) for a game to just shake for no apparent, well-integrated reason. Plus I did the speaker+subwoofer upgrades because of the soundtrack, so I already have a well-integrated shaker motor! (When it comes to rock band/heavy metal games, get/add the top-of-line speaker and subwoofer upgrades. Trust me on this: you won't NEED a shaker motor after that upgrade.)
So for BKSOR, my $0.02 is to put the shaker dollars towards the sound system upgrades instead.