Having just left Mara Plains, a few points to update on:

• Barely a week ago they upgraded their Internet. It still went down a few times for 5-10 minutes each time, but it's now 15 up/down, so good enough for basically anything. I was able to download a few episodes of BBC's The Hunt to keep me occupied during downtime.
• Hot water bottles are now included as standard in beds, but we never got them included in any camp during the morning drives - Singita Grumeti included.
• I agree that the food could be better. I really do not like buffets for lunch either.
• Horseback riding is now available to Mara Plains and other camps. We saw a group going up to the 5 cheetahs and then sensibly galloping away.
• We also had room #7, but the smell from the river was so bad we had to move. 5 hippos had created their own cesspit barely 20 metres away, plus decided to do early morning races between themselves, so we moved to the delights of room #4. This actually did get very warm, so we had to use the fan at night. We also had issues with thousands of flies coming into the room, so those nets may have been a good idea after all.

The game viewing was similar to your own - absolutely unbelievable. Easily the best we've ever experienced. Both Singita Grumeti and Mara Plains was a bloodbath. At Mara, we saw 2 successful hunts in 2 consecutive drives; first the lions, then the 5 cheetahs.