Have not stayed at either, but they will offer different wildlife experiences.
Phinda Forrest lodge is a private individually fenced game reserve of 74,000 acres in the Kwa Zulu Natal province, in the SE of SA. The challenge with such individually fenced reserves is that, while large enough to sustain a full subset of SA wildlife, there is little genetic diversity, and the game numbers low enough that they have to be heavily managed (lion numbers may grow beyond the ability of ungulates to sustain them, so they are moved or culled, perhaps a drought wipes out the small hippo population so they have to be reintroduced, etc.). I am not being critical, such game reserves fill an important niche (providing a “reserve“ to certain endangered animals like black rhino, for example), and an average international tourist staying for a few days will still have a great experience and likely not be aware of the difference I speak of. Last year I took my parents to a private reserve and they called it the best vacation of their life.
Ngala safari lodge is within the greater Kruger National park. The original Kruger National park is fenced where it borders civilization but enormous, roughly the size of New Jersey at 7,500 square miles. There were originally numerous private individually fenced game reserves (like Ngala) bordering the national park and fenced, but a number of years ago these bordering game reserves worked together and dropped their individual fences and the fences to the Kruger, effectively adding another 700 square miles and making one larger park inclusive of all these lands called the “greater Kruger” and the result is these greater Kruger game reserves have all the benefits of an intact enormous ecosystem. For example, there may be a population of 20 lions at Phinda within the fenced area, whereas there are ~ 2,000 lions in the greater Kruger, free to intermingle and spread genetic diversity. The maximum elephant heard may be 25 at Phinda, but you may see a herd of 300 elephants in the Kruger. Since Ngala is still a private reserve, only Ngala safari vehicles can drive on its roads, and they can drive off road, so you still get the perks of a private reserve (exclusivity, ability for the rangers to drive off road unlike those of us within the national park who have to stay on roads).
I will also say Ngala safari lodge is within one of my favorite areas of Kruger, the southrn part of Central Kruger by Orpen gate. The landscape is an intoxicating mix of thorn veld, open woodland, with some occasional open savanah, and called “big cat country“ For a reason. Very healthy and dense lion, leopard, and cheetah country, and home range of 2 of the 3 white lions currently alive in the wild, part of the Birmingham pride, who frequently roam in and out of Ngala.
To be clear, both offer an amazing experience, and Phinda is a unique and beautiful ecosystem in its own right, but just wanted to illustrate a key difference. As for other options, any safari lodge within Sabi Sands, or the Timbivati, are within the greater Kruger and thus have similar benefits to Ngala. It is a malaria area, so anti malaria meds may be in order depending on the time of year. There are some private game reserves with the big five in the central North, West, and South of the country that are malaria free if that is of concern.
