Never heard of the Svetlana 12AX7, with the exception of the NOS version.
IMO the LPS sounds very good in V1 in a regular (i.e. non Roadster) Rectifier, as they are bright and can have the highs get out of control on the dirty channels. I would agree they are very smooth indeed. Very warm and round. By comparison, a Tung-Sol in V1 sounds kind of shrill in my Rectifier.