This is a difficult question to answer. On a wooden ride, there is no question. Lap bars are superior, especially with wooden rides' propensities towards airtime hills. On a B&M Hypercoasters like Nitro, Behemoth et al., the clamshell-type restraints mentioned earlier are the best, especially with the stadium-style seating on Behemoth. Even looping steel ones like, for example, Joker's Jinx at SFA are better with lap bars, despite the fact that they offer less security. However, on an inverted ride, such as any of the numerous Batman clones, OTSRs are just a little better. Lap bars on those sorts just seem a little TOO free.