Many things have happened since I last chimed in!
Got my SL-900 4 days ago. Absolutely all imput from users in this thread proved to be truthful and reliable. It's the closest thing to my -veeery limited- experience in all tube amps. Absolutely warm sound, dead right intor soul, blues, old school rock sound. No wonder that SVT or b15 users are turning to this thing...
...But...the problem was me: i came to realise once again that I'm a ss amp king of guy. It's given me the chance to appreciate all the goodness in my Markbass sa-450 amp. In terms of clarity, transparency and definition I cannot do without 70% of my playing time.
As a conclusion: I'll stick to my Markbass to cope for that 70% of fast response, ss warm cleanness and slap sound. For the remaining 30%, I have already ordered a DHA VT1-EQ bass drive pedal that won't nail the alltube amp sound, but will take me somewhere near...whereas i could not take the Streamliner to sound as i want for most of my playing needs.
My SL-900 is on ebay now.
Thanks to everybody for their helpfulness, wisdom and info on a truly outstanding amd that does what it promises.