I think it was pretty popular (totally guessing), probably 2nd place behind the C64 in terms of those home/game oriented 8bit machines. There were about the same amount of spectrum vs C64 games in the shops.
The weird thing was that nobody I knew had the same computer - in my circle of friends and family, there was a ZX81, my Spectrum, a Vic20, a C64, an Apple II, a TRS-80, a BBC Micro, and a friends family even had a Dick Smith computer (after some searching it might've been a VZ-300). Only the ZX81 and the Spectrum got any programming done on them though :(
The weird thing was that nobody I knew had the same computer - in my circle of friends and family, there was a ZX81, my Spectrum, a Vic20, a C64, an Apple II, a TRS-80, a BBC Micro, and a friends family even had a Dick Smith computer (after some searching it might've been a VZ-300). Only the ZX81 and the Spectrum got any programming done on them though :(