Nick uses it horizontal, I prefer it vertical. Works for me. I find the off axis disperion of mids/highs is spectacular. Probably because there is only one front firing woofer so, there is very little cancellation. It works as well or better than the mid loaded cabs I've owned in that regaurd. That spike at around 2.5khz really helps keep the high mids strong off axis.
I've been searching for a small cab that was "good enough" to get me through a gig when I couldn't used my big cabs but, this xsonics is more than good enough. It is doing what I want it to do, with a live band and it has it's own thing going on. This is a real world gig cab. I like cabs at home to be pretty. This cab is a hammer. At a live rock gig, you want a hammer. The pretty cab will get buried everytime. But, this isn't an ugly hammer. It can sound beautiful while still being solid in all the right places that make a bass sound good in a mix and on it's own. Apparently this is no small feat since so many company's aren't doing that.
And no, Nick isn't an engineer but, I think that through experimentation he arrived at a design that really works for him and thought that others would dig it too. He is a gigging cat like the rest of us and doesn't have time and money to blow on things that don't work. I can really respect that. He is alot like me in that regaurd, only he had the nerve to do something about it on a larger scale.