I'm currently running a Markbass TTE500 thru the matching 151RJ cab, and loving the sound! This is my first tube-ish amp, and the cabinet is super responsive. Because I want to get the full 500w want from the amp, I want to pair the cab. I'd also like to stay with the Markbass line, as I'm really impressed with the sound vs. weight, and I'm considering either another 151RJ or the NY 604. I'm leaning towards the 604 because I'm wanting something smaller than a 15 that I can use with the same head for small or upright gigs. Thoughts, ideas, suggestions? I may end up having to buy sight unseen on the 604 as no GC around here has one to try out. Thanks!