I always prefer tubes, in the past units all were using 12aux, 12atx
My current Cayin Integrated uses 6SN7 and 6SL7’s, I really like their sound. Based on their sound, 2 of my friends changed their Preamps to 6sl7/6sn7, both very happy with them.
Various tubes definitely sound different, I bought (6SN7 or 6SL7’s too lazy to look it up) from Brent Jesse, one pair sounded awful to me (compared to the original Cayin branded I blew up). He had me break them in for 60 hours (no signal, just on), I still did not like them, he let me exchange them, I got lucky, second choice, half the price, they sound terrific.
Meanwhile, someone changed their OEM Cayin tubes to a different type, and listed his Cayin tubes on eBay. I jumped on em.