I have to preface this by saying I formerly worked with two Forrester Alumni and when I approached them about the company they had rave reviews of their time there. One held the precise position I applied for and let after two promotions while the other was an Analyst when she left.
I applied via Forrester's website and was contacted within a couple of weeks by a recruiter to set up a phone screen. The phone screen was your typical explanation of the position, the salary, as well as questions pertaining to your resume, why you are interested in Forrester specifically, and whether or not you are still interested in the position after hearing the description, salary, etc. The screen went well and the recruiter doled out some advice about the next round which was a call with the hiring manager for the position. I did have to send a couple of reminder emails to the recruiter between the screen and the next phone call as we had not set an day and time. There ended up being a slight mix up that involved me not receiving a verification email for the call and therefore, I was not available to take said call (these things happen), but we rescheduled a couple days later. This phone call was similar to the first. The hiring manager wanted to be clear about the responsibilities of the position and then delved a bit deeper into "why Forrester" and some additional general background questions. This call also must have went well as I was scheduled to be brought in to meet with 6 people in one afternoon.
No mix ups this time, I was brought in on a Friday afternoon, not many people left in the office (you can have a life at Forrester apparently) and was promptly given a tour by the recruiter. I went through a grueling process of 5 interviews, one being remote with an Analyst in San Fran. There was a large amount of crossover in the questions (which from my perspective was redundant but that were asked by each interviewer, but each person had their own style, background, and personality that contributed to my own impression of the company. The order was: Hiring Manager for my position, Analyst (Senior Analyst? I do not recall specifically), Researcher, Analyst, Research Associate (yes someone in my current role was supposed to be interviewing me, pretty cool if you ask me). However, there was a last minute change where the RA became unavailable so another hiring manager stepped in to finish off the gauntlet at which point I could hardly form coherent words from having been speaking for the previous (2.5 hours?). Subjectively, I did enjoy meeting with a variety of employees in the team as it enabled me to get a better feel for the culture and atmosphere than at other companies I had interviewed with.
The recruiter told me I would be contacted by Tuesday evening about my standing and I actually was contacted by Monday and given a tentative offer which was formalized a couple of days later. I was in the interview process with a couple of other companies at the time, but I knew by then that if Forrester offered I would accept. Unfortunately there was no room to negotiate salary, but considering the company benefits (never forget about the benefits) it was palatable.