Advocate isn't the right word. I've rolled a few and know their character which means if I buy another 6sn7 amp I can roll the tube I want in without spending money again. But the 6SN7 tube is really fragile and getting a good one was not fun. Luckily I bought from a good reseller so I was able to exchange tubes that got damaged in shipping or went belly up early. There are some rugged 6SN7 varieties that also sound great though.