If you can get them cheap (i.e., comparable to whatever we would normally advise instead), go for it. Their cables are well-made, just way overpriced. I don't think any one type is any better than any other & personally wouldn't bother with the extra expense of a THX logo on the packaging.
I have to agree, I have both monster 2 and three mixed cables and see no difference between the two. I will say that the difference between monster 2 and regular cables (even monster one's) was drastic. That's been my own experience.