As a newbie all I would say is I love my own Mark 2 - (.22). I was collecting Webley pistols when I happened to notice an "unusual" looking rifle being sold by my favourite dealer (a member here).
I had never seen one before but was taken by the pure simplicity/complexity of the design - not to mention the precision. Mine is lacking the circular part of the peep sight, the swivel pin and screw of the barrel swivel (I have cut down a 6.5ml nail, blued it and cut what looks like a screw slot in each end - not to fool anyone but just to make it work and look ok) and the bolt "ball" has been re-welded onto the lever. However the general condition of the rest is great.
What I really like however is the sheer accuracy - my eyesight is not what it was but I can hit stuff using the open sights.
I too, however, would love to find a .177 barrel - just to compare how they shoot. Value/investment does not really interest me.
BTW - it has also got me interested in old rifles again - just bought a mint Vulcan and mint BSA Merlin.