The London Tower Bridge set is one of the larger ones available, has 570 pieces, took about 2 hours to complete, but isn’t as fun to build as Lego. The small size of the pieces can be frustrating. I got my sets from eBay, free shipping that took just over 2 weeks, without any customs problems.
LOZ [micro diamond blocks] is basically a Chinese copy of the Japanese NANO BLOCK company, which in turn is a miniature version of LEGO.
LOZ is a good alternative to Nanoblock, it costs less, quality is decent considering its “knock-off” nature, and finished pieces are great displays.