I have just done a quick stint through Central Europe and the UK & Ireland.
Travelled with a Central Europe LP and and Austria-Switzerland Lets Go.
Lets Go makes too many mistakes with their maps, telephone numbers and recommending crappy hostels.
Lonely Planet had accurate maps, accurate directions to hostels, cheap eats were cheap and suggested places to go did not constitute a complete travel plan.
Lets Go spent so much time crapping on about places to see it should not be considered a guide for the independent traveller, it is a spoon-fed guide to seeing only what is in that damned book. Pity so many Americans seem to use it, they miss a lot of other great stuff to see.
Lonely Planet gives better history and background on regions so you can understand the place just a little before getting there. It means you can follow interests rather than a Lets Go style itinerary listed as things to see.
Rough Guides are next best, though a little wordy. They are accurate but boring cf LP.
Rick Steves has been bagged nearly enough. They are guides for Americans only, the rest of the world wants to spew (please clean up with pages from Lets Go – at least then they’re useful).
Merely my opinions, others may beg to differ.