I had the 336se very early in my Head-Fi journey. It was my first tube amp purchase. Bought it 2nd hand but it gave me a lot of joy. Along with that I bought my first 2 headphones - hd650 and DT880. 336se can be very erratic with tubes - some tubes would be quiet, others noisy, even though the tubes were ok. But when it had the right tubes in it, boy it sure did rumble.
I move up to the 339 not the 339i and the step up is significant. It's almost double the joy.
Fortunately by the time I got the 339, I had a lot more tubes and a lot more that were acceptably quiet and sounding good. With the 339, my ears were opened to what is possible with a good tube amp and headphone. Been through a lot of tube amps since then but the 339 still thrills.