Hi, yes I have both the Byron and Alabaster, plus the Sedley phono amp. Lovely kit from a small British manufacturer. I have had the Byron for about 12 years now, and managed to nab a secondhand Alabaster about 3 years ago (they don't come up on the secondhand market very often - a testimony in itself).
The Alabaster has a lovely "musical" sound if that makes any sense! Quite a rich sound without being overly warm... I've read more than once it being described as a cross between Naim and a Sugden but as I've not heard a Sugden myself that may mean more to you than me.
The Byron is about as close a sound to vinyl that I think you'll get out of a CDP at this price level. Very organic and quite smooth, it never fails to put a smile on my face
Yep, love my Sonneteer setup, as you can probably tell. Can't see me ever replacing either component unless I win the lottery one day, and even then I'm not so sure I would! (I would love to give the Orton a listen though).
There's quite a few threads over on PFM regarding the Alabaster, in particular from Naim owners which might give you more insight into how it compares specifically with the Naim stuff.