As someone who attended CMU for an MBA and took product management courses in the SCS, it's likely worth it. The classes I took from SCS around use-case driven design, project management of software projects, and platform strategy were some of the most directly-applicable classes in the entire MBA program.

By way of comparison, I think an MBA from CMU runs somewhere > $110k these days. It is one of the most expensive schools in the country (largely due to its until-recently-non-existent endowment; a rarity among top private schools). Hopefully once the settlement with Maxtor shakes out the school will end up with a healthy endowment (I know they're not getting all $10B but $2B would be a nice start for an endowment).

Also, I reject the statement that as a product manager you have no control over the resources. In a product-focused matrix organization, the product manager is ideally responsible for P&L over the product, which means they absolutely do get control over budget. Product management has changed a lot over the last 10 years, and what used to be a powerless position that was a glorified business analyst is now getting budget and control as tech companies reorganize themselves to look like CPGs.