A two-headed monster, the BA/PM Hybrid. I started out calling them Jekyll & Hyde, however I realized that is not the appropriate representation of the dichotomy of a business analyst and project manager within one person. Jekyll and Hyde are drastically different personalities of the same person, however, at any given time only one is present.
The internal battle is much more difficult for the BA/PM hybrid because both minds are present, and often conflicted with each other, at the same time.

For example, the Business Analyst finds that a stakeholder need is different than the project team originally understood. By no fault of the BA, simply an evolution and elaboration of the need. As a user advocate and the person ensuring the solution delivers business value, the BA knows this means a bit more time and effort, and potentially some rework, must be done to achieve this need.
At the same time, the Project Manager looks at this conundrum and immediately assesses the impact on the schedule and budget. The PM thinks that the business users may just need to make do with what was originally scoped.
Now the BA and the PM duke it out. We have seen this scenario numerous times on many projects. In this case, however, it is a BA/PM hybrid and the battle must take place within.
Ok, that is not entirely true. Just like the case where the PM and BA are two different people, many other resources can be consulted and other data taken into consideration. At the end of the day, these decisions are never easy but it can be more difficult when you’re the one wearing both hats.
So, there is some internal conflict – does that mean I think that the hybrid role is a bad idea? Absolutely not! I think the BA/PM hybrid makes perfect sense. You get the best of both worlds and are combining together the two functions that truly drive a project to deliver value. It’s just one of the many hurdles to overcome but you will find the people who can do it are going to be amongst the most valuable in any organization.