For the money, Sage 100 is a good distribution system. That doesn't mean it's a complete, robust distribution system. There are many features that the tool is missing. However, it covers a lot of ground.
The challenge is like most tools. There are features many people will never use. There are other features that don't exist that seem obvious to some, due to their business processes. However, those features would only be useful to a subset of a subset. If those same people purchased a product containing all the things they may want, they would probably complain about paying for a ton of features that they will never use just to get the few they want.
It's like someone who wants a top of the line audio system that only comes in a Lexus but they don't want to pay for all the other features in the car. They want a Nissan Altima with a Lexus sound system. In this case, they have three options: 1) pony up for the Lexus, 2) buy the Altima and be happy with it's sound system, or 3) buy the Altima and install an after-market sound system. In this case, you are the provider of the after-market tunes!