Relatively close. It's hard to differentiate when testing since melee can be blocked and missed, so the constant chain isn't visible.
The monsters in the tower have really broken DX and AC, no use trying to be them :x
I agree with coolbluex, don't add stat points into DX, you can remedy it with DX fortunes and active buffs depending on class, compounds.
1. As you get higher into levels, most of the time you'll be skilling your way through mobs, so melee won't help much in exp per second.
2. Even if you do have naturally high DX, the amount of attribute you have stacked won't allow you to continually hit mobs melee-wise, since you'll be OHKO'ing them mostly. With the exception of bosses and high HP mobs.
3. If I remember correctly, DX is capped at -50?