I would like to share my experience with Kraken. There are many people like me who are new to bitcoin and people try to find a secure/robust way to trade bitcoins. So I think it is better to share experiences with these kind of services.
Simple summary, I made a bank transfer in December but forgot to add reference note. I amend my changes same day and add reference. However, it did not show on kraken.com and my journey started with them. The main issue is they don't have enough staff to deal with customer issues. So if you have a problem and you need customer support, you are in big trouble. I opened my support ticket 12.01.2017 and I am still waiting 05.02.2017. Here is the proof of my journey
This is a long time for bitcoin world. I recommend people to stay away from this service, because if anything happens outside of the normal flow, you are literally alone.