I loved my 40.1's they sound awesome and are a beast! The only bad thing is i had a VERY hard time getting it fixed by the company or anyone else for 3 months because they weren't under warranty so i had to sell them both=(. I would definitely vote for the 40.1 in any case though they are bad a$$
The DD Z1 like to go poof amp be gone, but does alot of power, and i have seen alot of 40.1s go up in smoke to, but there both good amps, and do alot of power, kind of a toss up!