I was considering the 394ii, but I've already got a couple of beastly SS amps (OG Cavalli Liquid Gold, Mjolnir BiPolar), so I opted for the 433 at less than half the price. Of course after hearing how good the 433 was, I started wondering about the 394ii...
Unfortunately, since owning the 433 I haven't had a Susvara, 1266 or any other really hard to drive headphones to test with the 433. However, everything I've thrown at it from planars to 300ohm dynamics has sounded great off of it. It has a pleasing analog feel, so just a slight touch of warmth. I think one of it's most impressive abilities is how well it stages. While it's not a ultra wide, everything is presented right where is should be.
I'm working on a review of the 433, but it keeps getting delayed. I've had some hearing problems the last 4-5 months, which hasn't allowed me to listen to headphones much.