The Jazzmaster was Fender's great ergonomic design.  It was designed to be really ballanced and comfortable.  It has two volume/tone circuits so you can dial in rhythm and lead settings and quickly switch between them.  It has thin/wide single coil pickups similar in design to the P-90.  It has a full floating tremolo unit with a trem-lock feature - way before it's time.  The 25 1/2" scale length will feel much like other Fender designs.  The wiring diagram is too complex to put on the plan, but it can be found here.  For an explanation of the controls, go here.