Having just returned from this trip I can second everything Sally has said.
Yes some of the drives are long but it was a good chance to get to know the others in your jeep, we played silly games to pass the time, watched the amazing scenery go by and some even managed a little snooze to catch up from the early starts. Even though some of the drives were hard work there were plenty of stops to stretch your legs ( and spend money) and it was worth it once you arrived at the lodges. The journey between the first and second stops was the longest, made worse by getting stuck in the mud, a flat tyre and traffic, we arrived a lot later than planned but even though we didn't have as much time, the views over the Water hole and sights of Mount Kenya in the morning made it better.
All of the lodges were really comfortable and the staff really welcoming - all with amazing views.
The drives themselves were unbelievable - we saw everything we could have asked for plus much more. Elephants crossing the tracks in front and behind us, that close they were brushing past the jeep.
Prides of Lions, with lots of cubs (very cute and mischievous, always wanting to play) - One group we counted 14 together.
A lion sitting in a tree - which apparently is a very rare sight.
Plus a Cheetah with two cubs just after a kill and a Leopard hiding in a tree.
Too many other animals to name and loads of various birds.
We had a couple of pretty heavy rain storms, which didn't stop us seeing anything, in fact the lions seems to appear more after the rain. Other than that the days were warm, nights cooled a bit, some found it colder than others but three of the lodges had fire pits so it was nice a toasty to have a drink with the group and talk over the day before bed.
If you love wildlife, beautiful scenery and want to see the life in Kenya this is definitely a trip worth doing.
I'm so glad I picked this for my first JY trip - Brilliant memories I will have forever.