Greece

Maybe he has never been there? Not been particularly impressed with his Greek (Athens and Peloponnese) guidebook.

RS guidebook is not a thorough guidebook for a country. He picks his areas and does them very well, but he is by no means all encompassing. Our guide for the RS Greece tour was from Thessaloniki, Greece's second largest city, and highly promotes going north to their wonders, but you need to find a different guide book in order to do that. One that is more thorough like Lonely Planet, Rough Guide, etc. In fact you should never just rely on one guidebook...IMO. YMMV

Check the Lonely Planet guide--there is a lot more information about northern Greece. There are many archeological treasures in northern Greece as well as beautiful mountains, quaint villages, and wonderful food. Prespa is the far northwest corner and it is a wildlife refuge with rare birds, a beautiful lake, an 8th century cathedral on an island, and many other ancient churches to visit.

I usually buy 2-3 guidebooks for a trip. If I'm going to spend thousands of dollars on a trip and a significant amount of my vacation time, I want to feel comfortable that I'm taking the best trip possible for my interests and budget. RS readily describes the criteria that he uses in his restaurant and hotel recommendations; some of that has to do with the personal experience you're likely to have with the hosts. I like having a broader choice of ideas to work from. I think the RS books are also more geared toward the first-time traveler to a particular location who wants to see the big, main sights that most tourists feel are essential. One thing I like about the RS books is that they describe sights that he knows his tour groups enjoy, and provide detailed transportation and ticketing suggestions. They provide info that the first time traveler may be nervous about handling. Other guidebooks are generally more comprehensive on a country-wide basis so you get that broad perspective. They can provide less 'on the ground' tactical detail and can sometimes bewilder if they don't provide any sort of qualitative rating of sights. Using the RS guidebook in concert with another book kind of gives you the best of both worlds. Our trips tend to be a mash up of both, but resembling the RS itinerary the most. We haven't repeated a country yet so we're habitual first-timers : )

My own favorite is ROUGH GUIDE to GREECE ... R Steves Guides as others have said, cover the most popular sites tin the Peloponnese and Athens Area plus Delphi, and that's about it, plus a page for one island -- mainly what his paid tours cover. His guides are very good for D-I-Y walks around Athens, the Acropolis & the Big museum, plus, this site offers free Audio downloads of same. HOwever Rough Guide gives in-depth background, including ALL the islands & N. Greece, plus very usable maps. Lonely planet is more succinct, v. good on logistics, less in-depth on ancient history or mod. history, or archeological/architectural stuff.

I'm one who agrees that if you are spending many thousands on a trip, why skimp on paying a few dollars for guides? You can always browse the guide shelf at a good library, and then buy those that seem to appeal. Important note; online you can buy used copies both new and previous editions .,.. and it doesn't matter terribly if you get the 2014 or 2016 edition vs 2018 -- you are not getting them for the latest hotel & dinner prices, but for the overview and landmarks, and these don't change much. As a matter of fact, the latest editions of most I find are cutting texts in favor or room for color photos, which you DONT need - that's what the internet is for.