I have owned around a dozen Krakens (6 right now) and rent them out all the time. I would say get a kraken. Downgrade the spring (or cut a few rings off) shim and relube the box and you will have few to no problems. I have had a some of my guns for a few years and anything that's broken has been cheap and easy to repair. I have had no regrets buying a Kraken.
www.mechbox.com is a great guide for getting the AK apart and back together.