Difference between LEA and MOVE.L?

In this case, there will be no observable difference (unlike the accepted answer claims - the MOVE example will assemble as MOVEA which does not alter the CCR, see M68K Reference Manual Pg 4-116 to 4-120).

The lea instruction does not affect flags, where the move instruction does. Specifically Z and C will be cleared after the move #$1000,a0.