As far as internal recruiters go, the team at Gartner was impressive in their ability to coordinate and communicate. Everyone I spoke/met with was professional, friendly and helpful--always following through with next steps in a timely fashion. There's a good reason why Gartner is listed in the top 5 toughest interviews but if you do your homework, listen to all the advice from recruiters/hiring managers, and go out of your way to ask current employees for help you'll do great.
After being approached on LinkedIn the process included: 1) an initial phone screening, 2) a phone interview with a sr. recruiter, 3) video interview with hiring manager, and 4) in-person mock pitch/final interview with several members (sr. recruiter, hiring manager, VP of sales, another director of sales).
Aside from their goal to figure out your ability to exceed sales goals they are looking to evaluate your executive presence, business acumen and coachability. Ask a lot of questions (about the company, job, vision) and prove that you'd be a valuable asset to the team. For the mock pitch, do your research and try to draw insights on possible pain points that your "client" would be facing. You're not expected to know specific pricing on Gartner products or services but you should have an idea of general next steps that BDMs are expected to move through.