My wife and I are in our 60s, and travel light -- with one change of clothes, two toothbrushes, a laptop and two cameras. We spent 7 weeks in central Turkey in 2010, 10 weeks in 2011 and are returning for 11 weeks in 2012. We travel cheap, without an fixed itinerary, and use inexpensive lodging and eateries.
The Lonely Planet guide was our travel bible. Whenever we met another trekker (as opposed to a tourist) we found that (regardless of nationality) a worn copy of Lonely Planet protruded from his knapsack.
Lonely Planet is not for upscale tourists; they should use a Frommers (which is useless for us). One drawback is Lonely Planet's popularity. We repeatedly found that any hotel well-recommended would raise its rates 25% to 50%. We would go to a "lesser" selection.
Are there shortcomings? That is a moot question, since there is none better.