Ooh, this is most interesting. I've been using the THDI for a few months now and really like it. I'm not really one for pedals, I just like to get a great tone and keep it simple. That said, a usable drive on the THDI, rather than having to basically choose AGS on or off due to the volume boost, is surely a feature that many have been crying out for.
The best thing I can see, which surprisingly nobody has mentioned yet, is the addition of 3.5mm headphone out and aux in, which I think is fantastic and was the main thing previously lacking for me. So many preamp/DI boxes have that feature now, that Aguilar were being left behind in that regard, so it's great that they've addressed it now. I also like that they've gone for a VTDI style enclosure, and moved the DI from the top to the left, along with the Pre/Post & Ground Lift buttons. I wonder if there is any weight saving, I mean the original is a hefty beast.
The knobs look great and I even like that the writing has gone below them this time. The top jacks have remained and it's still 18V, presumably analog too. Looking forward to the release & videos of this thing. The headphone addition alone might swing it for me, I love the thought of plugging straight into my board without having to use an extra jack lead, plug my practice amp in and plug my headphones into that.