Advantages and disadvantages of BPMN?
It's largely down to audience and purpose. In terms of modelling language, BPMN and UML activity diagrams cover pretty much the same conceptual space with different notations. The notation thing gets religious very quickly. I personally prefer AD notation over BPMN - but it's a very personal thing.
Broadly speaking, BPMN tends to find favour with those coming from a business process modelling / business analysis background. UML ADs tend to be favoured by those coming from a software perspective. Tool support tends to mirror this: the high end process modelling tools (casewise, aris, etc.) are more likely to support BPMN; software modelling tools (MagicDraw, Sparx, etc.) favour UML. However there's increasing crossover there. I've used both with business stakeholders with no issues in either case.
Finally is purpose. Are your diagrams going to be for human consumption only or used as a specification for some form of analysis/code generation? If it's not just pictures then your tool chain may well be the deciding factor.
If you want a more detailed description of the differences, have a look at the answer in this forum post.
A new BPMN Profile has been discussed at the OMG. UML can easily generate code even with an activity or state diagrams. You just need to add stereotypes in your model then a parser will take the xmi and create code. The OMG specification will define which stereotypes should be used and why. Really a very good idea !!
In my company we have stopped using BPMN and are only focus on the activity diagram which is more accurate because built on the top of a standard language. Having also class diagram, usecase and activity diagrams allows to model faster. We get a running code from our activity or state diagram. We debug with our class diagram. We use the same metamodel for all diagrams and therefore can trace activity to code implementation and through class diagram. I mean that the code is reversed once generated and then we check all requirements and the architecture in order to have a nicer object architecture. Everything works well :-)
We are now waiting for the new profile specification and will implement the needed stereotypes in order to cover BPMN. My answer to your question is that we don't need anymore BPMN and should move on to UML 2.3 BPMN profile implementation.
BPMN is for modeling business process flow, isn't it? That's not exactly what UML is for. The goal of UML is to model a software from different view and ultimately not to have to code it (yes that's kind of ideal).