Really good watch, would watch again, and can recommend.
I like the mystery aspect of this romantic comedy, while it is somewhat unrealistic, it's somewhat refreshing to have a legitimately "good" guy concept. Legitimately getting to know 100 girls is quite the effort, and while the actual mystery isn't so complex, it definitely lends to a lot of character work during his sleuthing.
Jonathan Tucker looks like a poor man's Joseph Gordon Levitt, meant a complimentary as possible, but does really well leading the movie without carrying it. The ladies (and James DeBello) pick up plenty of weight and we see some familiar faces: Larisa Oleynik ("Secret World of Alex Mack", "10 Things I Hate About You"), Katherine Heigl ("27 Dresses"), Jaime Lee Pressly ("Mom", "My Name is Earl"), and Emmanuelle Chriqui ("You Don't Mess With the Zohan").
Cast is good, the writing is solid, the delivery is charming, but the concept lends to a lot of throw away material. This is probably true of most mysteries, but there is little one clue leads to the next in this: it's mostly 99 dead ends.
They do some cute work at the end of the movie to alleviate some of that, but by then, the actual story is over, and even I checked out.
Great little rom com, they let the jerk guy be a side character this time, and I think it is very much worth the watch.