I've known about Gru for quite some time-- I remember one of his videos having 200,000+ views on Youtube, so he's something of an underground hit. I like most of his stuff, but I find the same problems that consistently appear with djent (yes, it's djent).
It all seems very repetitive and very crunchy, with little melodic or harmonious sound, like a wall of sound. Some of it is good, but most of it sounds extremely similar. It's good, but there isn't much diversity. But Mr. Gru is talented, he can't be faulted for that.