The first reason for the bad rating is that there is a TONE of code. The MP-Layout-1 homepage has almost 2400 lines of HTML. I don't want to even start saying about the CSS that it's poorly organized and you have to check out a lot to clean what you don't need. I've purchased other HTML bundles for the half of the price of this one with no more than 1000 lines of code and much better organized CSS.
The second reason is the price. I've looked at the price a few days ago, it was 23$. I've purchased it yesterday, for the price of 29$. I check it today, 23$ again. You gotta be kidding me. This is my worst experience so far on themeforest.
You cannot beat good customer support, and that's what I got.