The interview process was excellent and the support throughout was superb. The process took 2-3 months during the summer period. It involved standard recruiter interviews, an in-person interview and a panel presentation. After the panel, I had a more causal conversation with a VP from another geography before I received the offer.
Salesforce has by far offered the greatest interview experience with much support from the company. You have to put in a lot of effort to succeed but the company does the same in evaluating you, so it's pretty fair. I am looking forward to joining a great team in London.