Waku Waku 7 for sure. Ninja Master's and Breaker's Revenge are also close. Waku Waku 7 is solid and a lot of fun. If you like Last Blade you'll enjoy Ninja Master's. It's definitely got a "prequel" feel to it, and Breaker's Revenge isn't so flashy but it's got really tight controls.
Anyone with a Neo should try to pick up all three of those really.