They're everything you imagine they are. Some other business class might give you more room or perks, but lay flat beds are extremely rare (only other example off the top of my head is the A380's private rooms).
Lie flat beds in international, long-haul business class are common enough that I consider anything else Premium Eco. For example, Norwegian Premium is sold as Business Class (J), but I've been just as comfortable in British Premium Economy. They are priced about the same.
