Sooo it's the same size as my THDI, the drive set up works like the AGS should have, it can sound like my THDI, and many other preamps in time...
Sort of feel like it's a losing argument keeping the THDI...
Don't forget the NuX also has cab IR's built in, Aux In/Headphone Out for silent practicing, and a Noise Gate as well. And it is smaller.
Now, having said that, AGS has much more drive on tap than the NuX Drive. So if you want heavy gain, the TH wins. The TH can also drive a power amp I think. Not sure the NuX can. Also, the TH can run on batteries in a pinch, the NuX is power supply only.
So there are pros and cons to both. There is also the question of emulator (NuX) vs real thing (TH). My opinion is, the emulator doesn't have to mirror the real thing, it just has to sound good generally speaking. However, if you are looking to drive a power amp and get true, authentic, Aguilar Tone Hammer sound out of your cabinets, the TH may be better. Though in a mix not sure how different they would be.
I've owned and used the Tone Hammer DI. It is a fantastic preamp/DI. For $175 I would rather have the NuX personally. I use external boxes for heavier gain, prefer the IR capability, don't need to drive a power amp, and would use the headphone practice amp often. YMMV