Thanks to an employee referral, I was asked to come in for a group interview. The group interview consisted of about 15 people and each person was asked 3 questions. Nothing out of left field, the one Q you might not expect was "if you could change one thing about Achievers, what would it be". After the interview I was told that they thought I would be a good fit for two departments, of which neither had openings. ~1 month later, I received an email asking me to come and interview for a position that had opened up. 1 phone interview, 1 co-worker/team-to-be interview and one TopGrade interview (look it up) later, the process was complete (all in - about 3 months). I was told that it was down to me and one other candidate and I did not receive the offer which was a really big let down after 3 months, countless thank you emails, follow-ups, preparation etc. but I cannot hold much against them.
HR can be a bit frosty at times but if you are into a fast paced environment then you should be able to adapt accordingly. Make sure that you let Achievers know what you can do for them, even during the Topgrade. I considered the TopGrade more of a personality test so I let off the sales aspect a bit and I think that that is what held me back in the end. If you reach the topgrade and prepare properly you will learn a lot about yourself.
If you're not a type A, I don't think you will succeed at Achievers. I will be keeping my eye on the job postings and have not let them out of my sights.