I own a SF Line 3 and had it upgraded to Signature (SE) about a year ago. Yes they still fix and support the SF equipment. I love this pre amp.
Got curious about new designs and have been auditioning other preamps. For full disclosure I own a Krell KSA200s amp, Revel Studio Speakers, and a Sony 777EX SACD/CD player. So far...
BAT VK-51se - had this for a week. Its a very nice sounding preamp, but I would not trade the Line 3 for it. BAT has better base, not as good high end, better sound stage by a smidge, and what surprised me is not as musical (I guess I'm focusing on the harmonic structure of the music.) The two have about the same dynamics both micro and overall.
Now have a Calypso....Next an Ayre k-1x so stay tuned.