Went on safari in Tarangire in Sept2013. This was one of 4 areas that we visited on our trip. Although we did enjoy this park (and especially our camp) it was not as 'exciting' as the other 3 areas we eventually visited.
This is a beautiful, peaceful location packed full of elephants with beautiful marshy areas unlike any place else we witnessed. The Tse Tse files were not as bad as reported (for us anyway). If I was forced to pick one area only for safari in Tanzania I would not pick this park BUT if able to make multiple stops then its something that I would add.
Its a good place to start instead of end your journey in Africa.
Read more details here on my trip.