In general, Kenya is the better know safari destination, but consequently most of its prime parks and reserves are considerably busier than across the border in Tanzania. With a safari tourism model that tends to prioritise quantity over quality, Kenya has followed the route of low value and high impact tourism.
By contrast, Tanzania subscribes more to the model of high value and low impact tourism, which means you might have to pay somewhat more to gain access to explore many of its protected areas and prime attractions, but the upside is that very few of these areas will feel completely overrun by tourists. In fact, many of Tanzania’s protected areas feel downright wild and remote. Tanzania would get our vote over Kenya if one is looking for a wild, relatively quieter safari experience, although both have their attractions in equal (but different) measures.