For natural big animals, Katavi National Park is the best
WILDLIFE
Compared to other Tanzanian National parks exclude Ruaha and Ugalla Game Reserve, Katavi has got very big and attractive animals, actually, when you see them, you'll feel the presence of nature to these animals and how wonderful they are. For example, when you look to an Elephant, it looks huge and giant compared to elephants from another National parks.
SCENERY
Katavi lies on Rukwa or Western rift valley basin, from around the edges of the park there is gentle slopes with heavy natural forest and at the center of the park its plain grass land like 10km square (Estimate) and at the middle there is a beautiful lake known as lake Katavi and Chada where you can sit and enjoy nice view and animals. Therefore the scenery is beautiful.
WEATHER
Katavi is experiencing two seasons, wet season which starts from October to April/May (Hot season) and dry season which starts from May to September. Depends to what events would you like to see, for example if you want to enjoy lots of Hippopotamus and lion, visit lake katavi and Chada during dry season and for nice birds, baboons, giraffe, elephants and buffalo, visit during wet (rain) season.
In short, weather is nice and I haven't heard any problem about weather.
ACCOMMODATION
Starting from Mpanda Town which is near Katavi (40km), there is hotels, lodging and guest houses all of these differ in status and cost.
Inside Katavi National park, there is Hotels, guesthouse, bandas (kind of small houses with one room self contained) and Camping sites.
FOOD
In Katavi there is variety of food, but also you still can take your own food provided that you don't feed to the animals like baboons and chimpanzee.
TRANSPORT
You can access to Katavi National Park by air, if you lodge a private flight, you can land at Mpanda Airport or direct to Katavi National park air strip or use public flight (eg Precission air) from Dar es salaam to Tabora and then catch train or bus to Mpanda from Tabora.
Using road, there is a main road connecting Mikumi, Ruaha and Katavi national parks via Mbeya, Sumbawanga to Katavi and Mpanda. This road at moment is gravel based though at moment there is construction of tarmac road from Mbeya to Katavi and Mpanda then to Kigoma. From Mbeya to Katavi, the road is good in all weather though in some places is a little bit terrible during wet season. From Kigoma to Mpanda, the road is accessible only during dry season untill when the construction of tarmac road is finish.
Alternatively you can catch train or bus from Tabora to Mpanda, or catch a bus from Sumbawanga to Katavi.
In short road transport is accessible and not bad but not reliable just like in other National parks until when the road construction will finish.
GUIDE
Tour and guidance in general is good because the administration is trying to attract more tourists to this place as it was not famous before compared to other National parks though it starts to emerge very quickly after many tourists discovered that Katavi has the best big and natural animals.
Therefore, to me, I recommend that if you want to enjoy for the best animals, go to Katavi National park, you'll feel it!