I've basically decided I'm going to get this lens, and have been actively shopping around. A couple of questions about value, especially if I eventually decide to sell it: 1) Lens comes in two mounts: M-mount bayonet and LTM. Is there any reason not to go with the cheaper LTM? I know the LTM can be adapted to M-mount. 2) Some offerings include the viewfinder, which of course I won't need with my NEX body. But given that a new VF costs $170 and only rarely appears on the used market, am I better off purchasing a lens + viewfinder if I ever want to sell it? It seems like the VF adds an extra $50 to the purchase price, but more importantly--would I be severely limiting potential buyers by offering a lens without VF?