I think you have the picture about right. Manu and i2 are the big dogs in this nitch. Once you get someone hooked on your software they never change. Microsoft at this time isn't working on this type of software as far as I know.
SAP (SAPHY) is the fourth largest software maker in the world. It is a German company that been around for 20 years or so. The founders still own like 50% of the company and are filthy rich. Go to there home page for a deeper understanding of the company. They are the big dog that is in the ball park with Manu. But it will be some time before they have a compeating product. Manu and i2 rule. Both will win. Hang Loose The Market Hawk