Recently visited Seregheti NP too on our honeymoon in early July (see Ngorongoro Crater NP). Weather was amazing. Mid-eighties and no humidity. Being the dry season the tsetse flies and mosquitos were not a problem. Had timed our trip for the Wildebeast migration. The beginning of our Safari with Thomson tours (without the "p", which I highly recommend) started at Tarangire NP where the migrating herds had left the week prior to our arrival. However we caught up with the herds in the western corridor of the Serengeti NP. Amazing! A vast expanse of grassland inhabited by millions of animals as far as the eye can see. And best of all, not one radio-tower with flashing red lights to spoil the view in the distance. Coming into the park via the Naabi Hill gate and traversing the endless flat plain is truely a sight to behold. You realize what a small speck you are on this earth. I would recommend visiting early/mid-June to avoid possibly missing the herds in Tanzania (they migrate to Kenya). The Kirawira Luxury camp is exquisite. The people of Tanzania are extremely friendly to foreigners and the use of English is spreading rapidly, thus making travel more comfortable for us westerners. I highly recommend seeing this eden.