i havent tried them, but have heard them mentioned by some folks who have and the reviews are along the lines of "tough to beat for the price". From what ive read thusfar, they seem to be pretty vicious
I've got the 15" 750 running right now one 1k and it sounds great! Frank Yu has been very helpful with answering questions even a few months before I actually bought my sub! I hit him up on FB and message him often!