3700 was produced from 1976 and discontinued some 10 years later while 5711 has been in production since 2006. Some of the main differences are:
- 3700 is having a great JLC based movement - same as used e.g. in AP's 15202 while 5711 is having a manufactured movement.
- 3700 has only 2 hands while 5711 is also having the seconds hand
- 3700 is having a closed case back while 5711 is having sapphire glass back
- 3700 is slimmer
- the case of 3700 is made of two parts while 5711 from three parts. This sans that 3700 really opens from the hinged "ears"
There are many other differences but these are the main ones.
Best, Kari