I didn't actually get to the interview process but had a negative experience trying to schedule an interview.
I was contacted by a senior recruiter to set up a 15 minute phone screen, using their scheduly account. I received an email confirmation of the time and day of received a text message confirming the time I selected. The recruiter called and left me a mean voicemail 30 minutes before our scheduled call saying that they waited for me but didn't have time to wait around and that I could call them later in the day. When I got in touch with the recruiter at our confirmed scheduled time, they notified me that my original scheduled screen time no longer worked for them and they had rescheduled my screen a half hour earlier--but never notified me. I communicated this to them and their answer was "well it's on my calendar, so it must be your error".
Annoyed, but still interested in the position, I agreed to call back at the new time we agreed upon. However, I called the recruiter twice at the new time with no answer and their voicemail box full so I could not leave a message. The recruiter never called me back, but instead sent an email over the weekend apologizing for the confusion and asked to reschedule. I emailed and gave a couple times I was available for rescheduling and never heard back from the recruiter.
It's highly unprofessional and if this is how they treat job applicants, I can't imagine how they treat actual employees.