Popular with Americans.

Let's Go has shit maps and focusses primarily on what their editors deem to be the 'best' places to visit. This can be good if you are working to a limited timeframe, or you perhaps like to minimise on tough decision making.

Note that 'Nightlife' suggestions by Let's Go are well informed, and usually spot on.
This can be a real drawback with some of the other guides.
What looks good on paper does not follow to be 'good' in practice. Let's Go's emotionally loaded narrative sums up venues in a way which is funny, entertaining and saves you wasting your hard earned in bars you wouldn't visit or normally wish to visit.

Again, good if your itinary is limited.. Go for it...

Grown-up guides, perhaps more frank and witty than Lonely Planet.

Emerging roughly at the same time, Rough Guides were launched with a TV series hosted by Magenta Divine on Channel 4 which ran for a number of years.

Something Lonely Planet struggling to acheive, despite making statements of intention in that direction for a number of years.

Less political correctness and lack of shit places made to look good, mean you're getting what you're paying for with the Rough Guide.

 

Fodor's.

The French swear by them.

Personally never read one from cover to cover.
.

Travel Guide book.