The New Testament

For some time now, I have been curious about "Rough Guide", the British competitor to Lonely Planet. On this trip, I took along both the Bible (LP) and the New Testament (RG). My observations in one sentence: Lonely Planet has more information, Rough Guide is easier to use. For the winners by category, read below.
Data – LP.

Lonely planet lists more accommodations and restaurants. It also has some additional useful information. In Momostenango we received a private lecture on Mayan Cosmology by an indigenous teacher, who was listed only on LP.
Maps – RG (By a big margin)

RG maps of all scales (Regional, Local, and City) are drawn with more contrast and are easier to read. RG has more local maps, making navigation easier. On city maps, points of interest are labeled (not numbered), and to me, their method of indicating accommodations and restaurants seems more logical.

Organization – RG for drivers, LP for backpackers

RG arranges towns and villages in sequence of travelling along highways. LP clusters them around public transportation hubs. In LP the listing order seems to reflect their level of interest, rather than travel logistics.
Reading Pleasure – RG

The Rough guide style is more subjective and more fun to read.

Overall Winner - Lonely Planet

If I had to choose only one guide, I am a bit disappointed to say that it will continue to be the Bible.