The clones in 1996 and 1997 were fully legal and licensed by Apple.There were many clones that ran Mac OS 7.6 and Mac OS 8 on PowerPC 601, 603 and 604 based hardware. DayStar even made a quad processor clone and Motorola even made a clone that used PS/2 for the keyboard and mouse (instead of ADB - AppleDesktopBus). There were also clones from UMAX, Tatung, PowerComputing, and Radius. The home audio company Pioneer even made a clone as part of a HTPC setup they sold for a short while.
After Steve Jobs returned to Apple, the company did not renew the clone licenses for the newer G3 (PowerPC 750) based chipsets. (Cloners could legally use G3 CPUs from Motorola and IBM, but they were not able to use the rest of the motherboard chipset nor were they allowed to the the ROMs. Oddly enough, Apple eventually removed ROMs from their system architecture in 1999 with the second generation blue-and-white G3 minitowers, but the original beige G3 towers still had boot ROMs). I remember UMAX selling a clone that was basiclly a 604 based system but with a newer G3 processor card shoehorned in.
My college had several Mac clones, there were generally abouto 5% - 10% faster than the genuine Apples because they often had their CPUs clocked a little faster. Sometimes the clones were cheaper than an Apple, but more often they were priced about the same. Most clones used ugly 1996/1997 era PC beige cases, but at least they had plenty of drive bays.
If I remember correctly, PowerComputing (one of the first cloners) had a longer licenese witih Apple. As a result, Apple bought PowerComputing in 1998 when they pulled the plug on cloning licenses.