Marantz and Denon should be very much alike, and I don't think you will hear any significant difference. They are both owned by the same company, D&M Holdings. You will be happy with either one. Another manufacturer I like is Yamaha. Anthem, Emotiva, and Outlaw Audio are good too.
By the way, four Hsu VTF15h mk2s are going to blow your house down. That is a huge amount of power. If you actually end up ordering that, order that over the phone, because that sort of order might be less expensive to ship via freight versus fedex, so see if you can arrange freight shipping over the phone on that. There would also be less chance of damage occurring to the subwoofers.