Received response (email) to schedule a skills assessment roughly 23 days following online application. A phone interview was conducted the following week with HR recruiter. A video (webcam) interview was conducted the week thereafter with department manager and director.
Apart from the initially lag from HR to conduct a skills assessment and phone interview, the process was extraordinarily fast and easy. Gartner is a large company with multiple divisions at multiple locations, so perhaps the added time is to be expected.
The skills assessment was timed (~30 mins.), but the timing is on the honor system, which is extraordinarily tricky. The recruiter only noted the number of sections, not the number of questions, which is also tricky. Not a difficult test, but it's not for the faint of heart.
The interviews were very friendly. The interviews, however, were very pointed. The screen interview (phone) took roughly 25 minutes; they know precisely what they want, but they'll be honest about what the expectations are for that particular role/duty. The manager/director interview took roughly 1 hour; a mix of background experience questions and several of the "behavioral" questions that are more common nowadays. If you have experience, and you've accomplished a fair amount in your time, then you shouldn't have any problems at all. Listen to interview coaches, if you have them, and have your examples at the front of your mind. Always. They'll notice right away if you aren't prepared.