Quoted from Monster_Bash:

I have both also (and a BR)
BSD is a kick you in the throat kinda game. Open out lanes, lightning flippers and 6-7 degree incline and it can be a bitch. When I had it (it's at the pinsitters right now) it was constantly..one more game..one more game when I played it. Then I would go a while without playing it. About once a week I'd stop by for my weekly ass kicking..and get hook into 15-20 games on it.
WH2O is less of bitch. I've seem to mastered mine and see Vacation Jackpot more often than not. It's a more relaxing game than BSD if that makes sense. It's kinda nice walking up to a game knowing you have a legitimate chance at getting through the software
When I step up to play BSD I literately think...'alright bitch..I'm gonna kick your ass' (and usually I don't). When I step up to play WH2O i'm like 'gee..I'd like to play a game of pinball today'
Ironically BR falls somewhere in between those.
So depending on what kind of game you looking for..it's still a tough choice.
If I could only have one I'd probably pick BSD..I'm liking the fast paced, short ball time games lately
My order would be
BSD (slightly in front)
WH2O
BR