Cam Schitter Honestly I'm currently on my 3rd reading of this series and each book gets better up until the 4th. Personally the 4th book is the best. The final 3 novels are still great but they, particularly the final book, seemed rushed. But These books were written over the course of 20 years. The gunslinger was written when king was still young, he has polished his skills sense then and weaves a story for the ages in these books.
Gem Kosan Yes. The world of the Dark Tower has many fascinating nuances that are only touched on in the first book. In particular, the elements of sci-fi and fantasy become stronger and more fleshed out. I suggest you read book two: The Drawing of the Three and book three: The Wastelands. If you're not hooked by then, the series might not be for you.