NL leakbuster is ok if you have time to work with it and put effort into it. It is however based around one set of stats that the majority of winning players play so it cant suggest anything based on your own play style or point out leaks that are not in its database. If you have major leaks in your game though it does offer good advice and will help you plug anything major.
Depending on the stakes you play it may or may not be worth it. eg. if you play 50NL it is only one buyin so even if it plugs a leak that is costing you 0.1bb/100 it will pay for itself in no time.
Actually the stat ranges are one small part of what Leak Buster does. There are several other steps that offer advice based on what you're winning or losing with, and very powerful filtering where you can see specific post flop play and how you stack up against other winning players.
There's also algorithms they use to determine specific leaks based on how multiple stat ranges relate to each other. I think 50NL and below players will benefit a lot from all of the steps in Leak Buster. 100NL and above will benefit some from the stat range analysis, but mostly the benefit will be in the other steps which point out some very clear leaks no matter what limits you're playing. Easily worth the price of the software.
I think people get caught up in the stat ranges a little too much, and winning players at small and mid stakes might not realize there's a lot more to what leak buster can do imho.
