content: Acorn spawned ARM so of the two I would say Acorn was the biggest success. Also, having owned both Sinclair and BBC machines I would say the BBC was much more responsible for the generation of programmers that came out of the 80's. Sinclair's machines were mainly used by kids playing games but the BBC had a truely advanced structured BASIC interpreter, built in assembler and far better hardware. Plenty of games for it too but a much more all around accomplished machine, not to mention robust and able to survive heavy use in schools. The speccy simply wouldn't have lasted the same so the best machine definitely won.