This is some general advice for travellers in East Africa. I'm not expecting it to be a popular opinion and i'd encourage dissenting voices to reply; i'd rather be wrong on this.
I've been travelling East Africa for over three months, following Lonely Planet's "East Africa 2012". This book has "11 Top experiences" and I've tried to plan my trip around visiting most of them. Many of these top experiences (serengeti, kilimanjaro, bwindi gorillas, Nyiragongo volcano) are simply amazing world standard destinations that will impress everyone, regardless of where else you've been in the world. The list of top experiences also includes Lamu so naturally i had pretty high expectations; I'm sad to report that I was thoroughly disappointed with what i found.
If you've travelled extensively in the middle east (especially in coastal towns or ancient cities like Jerusalem) then Lamu town isn't going to make your jaw drop. The winding alleys, donkeys and local culture are all interesting sure, but better can be found in other regions not covered by this particular LP guide.
The same is equally true for the beaches. There's no scuba diving shops here (despite what the book says) and snorkelling trips to Manda Toto are only possible between october and march. If you turn up between April and September you'll be greeted with silty water and windy weather. I spent some time on Shela beach and it's nice enough in a windswept sort of way (think windward coast hawaii), but I wasn't at all tempted to swim there. This island isn't a tropical paradise, so if that's what you're looking for then fly to Thailand.
So my advice to fellow backpackers. If you're travelling through East Africa and you're having trouble fitting all the destinations into a limited timeline, then Lamu would be the first things I would suggest cutting. If you have heaps of time and decide to come to Lamu anyway then keep your expectations down; it's not in the same league as the other highlights of East Africa. This criticism also applies to Zanzibar and i'll be making a similar post in the Tanzania section
