The only game I ever pre-ordered and paid for was Big Bang Bar. Even then I talked to Gene Cunningham about his plans, and how realistic it all was, before I committed and send in my money. I even helped out in the pre-production of the game to make it happen.
BBB obviously had a certain status, which made me want to own one. I can't say that for any of the titles that showed up after that had that status, so I didn't pre-order. That being said I wish all upstarting efforts all the best and hope they will succeed as it will make pinball in general more interesting and fun. We've seen what happens when there is no competition around.
I am slightly tempted to pre-order TBL, because I see the potential and really would like to see DP pull this off and raise the bar for some of the other manufacturers out there.