While my personal preferences anoint Yelp for iPhone (review) the better service for its broader and more objective listings, Where for iPhone's (coverage) plotting of only partnered services will also have its cluster of followers. The bottom line is this: though serviceable, they both need work. Yelp's developers should hone the accuracy and breadth of this application's listings and stabilize performance against crashes. Where would benefit from letting users customize their choices by selecting or rejecting services from a longer list of location-aware partners.
See the particular take of each app in the video above.