I own an LS25mkII, and it's not as "tubey" sounding as some other tube-based preamps. IMO this is a good thing, as I find many tube designs to be overly warm and syrupy-sounding.
I feel it's a good compromise between the warmth of a "tubey" tube preamp and the detail of a SS preamp.
Oh, and another thing - it seems that any and every ARC thread draws ARC bashers out of the woodwork. Reb, Sutts - nice to see you guys don't disappoint! :-) Apparently the ARC bashers wait anxiously to pounce the moment they see anyone mention ARC.
Whatever floats your boat! ;-)