As someone who just returned from a solo tour(via local buses, trains and hitch-hiking) through Botswana, Zambia and Namibia with this book in my pack I feel I can review it more fairly than those who have simply looked it over while dreaming about a future trip.
While no single book can give an indepth look at every country, this one gives you all the information you need to travel through Africa on a budget. Best of all it is small enough to fit in your pack and well built enough to make it through the trip in one piece. I will be going back next year and this book will be coming along.
As you can guess, with only about twenty five pages per country, some info is glossed over or left out all together. Due to space constraints Lonely Planet left out some of the "where to go and what to see" advice but they made sure to include all the information relevant to transportation and lodging. If you need more indepth information you should buy one of the individual guides that cover each country you plan to visit along with Africa on a Shoestring.
My one gripe with this book is that it seems a bit too focused on the backpacker/camper type lodging. I personally prefere to travel like the locals and stay in guest-houses and cheap hotels and at times this book skips right over this information. The worst way to save three dollars a night is to pitch a tent on the ground instead of booking into a local guest house. When you stay at one of the urban campsites the only "culture" you are going to experience is provided by the young, loud, drunken tourists. Not my idea of fun.
If you are looking for a book that will make traveling in Africa trouble free you are going to be disspointed, that book does not exist and never will. In Africa almost nothing is easy and that includes travel. But that is part of the adventure.
If you want to see Africa without all the hassle then you need to talk to one of the travel agents who offer all inclusive tours for small groups in large overland trucks. You will get some nice photos but you won't really be traveling "in" Africa, you will be traveling "over" it, and you don't need any book for that.