It depends on where you're based I guess. If you're in London, print space are very good, but you can also go super high end and go to rapid eye or Bayeux for a premium.
I use come through lab in manchester and they're great.
Germany / world: Whitewall does amazing larger prints. I think everything they do is really great. They ship fast to the U.S., too. https://www.whitewall.com/us
Books are hard. Most of online services in the US farm out printing to a network of printing companies. You are not directly the customer of the printer. They often print your project with other people's projects, so there isn't an eye on quality. The color can be inconsistent. Black and white is especially difficult because it gets printed in four-color (you may get a color cast or low density).
Finding a local printing company may be pricier but if you're after quality, it's the way to go. Companies that use a HP Indigo digital press can deliver quality that rivals old-school offset presses.