Let's simplify this expression step by step:

First, let's simplify the fractions within the parentheses:
2+1/(3+3/4) = 2 + 1 / (3 + 3/4) = 2 + 1 / (3 + 0.75) = 2 + 1 / 3.75 = 2 + 0.2667 = 2.2667
1+1/(1+2/3) = 1 + 1 / (1 + 2/3) = 1 + 1 / (1 + 0.6667) = 1 + 1 / 1.6667 = 1 + 0.6 = 1.6

Now, substitute these simplified values back into the original expression and solve:
2.2667 - 1.6 = 0.6667

Therefore, the final result is 0.6667.