I have only been to Singita in Tanzania, but having visited Maasai Mara I can't ever think of going back to any place where off the road driving is not allowed, and where 5 or more vehicles might be surrounding wildlife at the same time.

When I first went to Maasai Mara I thought "wow this is awesome, so close to wildlife", and than I saw Singita Grumeti and thought Mara was an open zoo and Grumeti the real Safari experience.

I think if you will be going to Africa regularly you can do different things, but if this is a once in a lifetime trip to Tanzania try to go to the right place if you can afford it. For me that will always be Singita Grumeti. There really is a huge difference between your average safari camp and those special locations.