I currently have both a BAT 50SE and 5i and I love both of them. The 5i works really well with SS amps while the 50SE works well with both tubes and SS, provided you take Delancey's advice and couple it with a good system. I find the 5i has a slightly warmer midrange while the 50SE is transparent without being analytical. Since adding a 75SE amp, I have decided to sell my 5i, but only because the new amp mates better with the 50SE. On the other hand, the 5i was more satisfying with the VK500 SS amp. Can't comment on the 30SE. Good luck, you can't go wrong with BAT.
BAT VK30SE, VK50se or SF Line 3se
Has anybody compared ? List experiences? Thank You Miguel