Hey guys, I just purchased a THR10 I after trying a Katana Air and returning it. Now this is just my opinion but I think the THR10 sounds better than the Katana Air and has a more straightforward interface. I also prefer the Yamaha App to the Katana's App. I thought the Katana Air sounded like a toy. The Air's speaker had an almost "hollow", boxy tone. To be sure, the small speakers on either can contribute to that tone but I found it easier to tame or overcome that effect with the THR. I wish Yamaha had a tone library for the THR II but I've found useable tones for what I need. It's just a practice amp which now sits on my desk. Also the wireless system on the Air was prone to crackles and pops. I elected to purchase the non-wireless version. The price put me off but also the G10 relay has been recalled and you can't find them. The other advantages of the wireless version: rechargeable battery power and additional direct access to more amp models were not important to me. Perhaps if I was a busker the battery operation would matter but it's not worth it for the convenience it may provide in my house. The App gives you access to the additional models on the non-wireless version. I overcame the wireless issue by purchasing the inexpensive Getaria wireless system pictured below. It works great, connects instantly with no noise or latency issues. My final cost for both was $300 vs $550 for the THR wireless. I don’t know how it would compare vs the Positive Grid Spark. BTw, here’s what the app looks like: The amp does what I need and it takes up little space.