I've used a good amount of different plugins for custom fields/types/taxes but i most say that Kontrol IS the best of them. It's fast, easy to navigate, beautiful and all in all simply great. The idea of combining customization of contents,site options, SEO and admin menu management is simply genius and saves a lot of trouble finding the right plugins for the different purposes, as Kontrol is top notch in every field.
I have used it for about a month now, and the feature list in that short period has grown in a very positive direction and very fast. I have also been in contact with David about ideas and suggestions, which already was planned or in the unreleased version, so David shows great forth sight and the will to keep Kontrol a major player in the plugin business.