First of all, it is important to distinguish between Rhino Post Safari Lodge (not a tented camp, obviously) and Plains Camp (which is). Both are in the same concession (Muthlumuvi) in the KNP, and operate under the same flag.
It is also important to note that Plains Camp does walking safaris. They may offer afternoon/night drives in inclement weather of when the guests so desire, but the focus is on walking. The Muthlumuvi concession has a very limited road network, so if you do go on game drives, these will be conducted mostly on public roads in the KNP.
The road network on the Mluwati concession (Hamilton's etc.) is more extensive, but they still use Kruger's public roads for game drives at times.
Shindzela has exclusive use of an entire farm in the Timbavati, as well as almost exclusive traversing rights on a number of adjacent properties.
Hamilton's accommodation is the most luxurious of the three. The tents at Plains Camp and Shindzela do have electric (LED) lighting and en suite bathrooms, but no power outlets. The tents at Plains are much larger than those at Shindzela. However, Shindzela will close for most of January for a major upgrade. I'm not quite sure what will change in the accommodation department, but will find out.
Johan