Let me just say this:
1. This article is an opinion. It is not labeled as an "objective study" from a research firm. This represents my own view on the Spring versus EJB 3 debate. However, I do not consider my employment at JBoss has anything to do with it. JBoss is not even the spec leader in EJB 3.0 -- for god's sake! I did not shill for JBoss proprietary technology (like JBoss AOP or Hibernate). I am talking about "standards" here.
Plus, I did not attempt to disguise my employment at JBoss -- as the other poster found out, it is right there on my home page.
2. "Proprietary" means "non-standard" in the context of this article. You can have open source but yet proprietary products. Yes, as you point out, JBoss also have proprietary open source products that would lock you into JBoss (just like Spring is locked into Int21). But I am talking about EJB 3.0 here -- not JBoss's specific extensions. So that argument does not apply.
3. I gave Spring credit for pioneering DI. There is no question here. In fact, EJB 3 got many of its ideas from Spring. However, I am talking about the whole application's dependency on the framework here -- the integration piece. Spring ties you to a specific vendor. EJB 3.0 does not. That is a key point from the article.
4. EJB 3.0 exists today and I have seen people use it in product.