Don't worry, even with Cook, it still remains a lot of work to do in localhost. Design your database on paper first, then in 3-4 hours you are connected to Cook, and then you can download and finalize your component in localhost. Cook does a lot, but also will give you a lot of ideas, then you will not ennoy you on localhost.
Sincerly, Cook will remain online tool because it is really more easy to maintain with versions and upgrades. Sync is really painful and I do not like it. All softwares I use using Syn (Calendar, notes, contacts...) Often conflicts.
