We visited TZ in 2016 and would rate the parks best to least: Serengeti, Tarangire (elephants!), Ngorongoro, Arusha, then Lake Manyara. We did Arusha as a day trip first to get an intro and meet our guide. We wish we had an extra day in Tarangire and skipped Lake Manyara. Very good driver / guide through Roy, highly recommend them.