Answer
Both the box will experience the same net force.
Work Step by Step
Assume $k$ is the spring constant of the springs.
Consider the first box. If you displace it to the right by a small displacement x, both the springs get elongated and will try to move the block to the left by equal force $kx$ since all the springs are identical.
$$\therefore |F_1| = kx+kx=2kx$$
Now consider the second box. If you displace it to the right by a small displacement x, the spring on the left will get elongated and apply a force on the box given by $kx$ to the left. The spring on the right will get compressed and apply a force $kx$ again to the left.
$$\therefore |F_2| = kx+kx = 2kx$$
Both $F_1$ and $F_2$ are acting to the left direction.
$$\therefore F_1 = F_2$$
