Yes, they should run the same if everything goes as planned. The reason ebuilds are preferred is that many of the packages TurboGears depends on are already in portage: cherrypy, formencode, sqlobject, kid etc.
The problem is if you have any of those already emerged, you'll have to unmerge them before using easy_install because it will bail out because of conflicts. Doing a non-root easy_install should avoid that, which is fine for development, but we do want TurboGears in portage some day soon.
