Originally posted by mecrox
Yes. With Canon and Nikon you only have one mount to worry about and there isn't the risk factor of it being discontinued any time soon.
Who takes the greater risk: the one who puts all the money on one horse, or the one who spreads the money around? I'm well aware of the FUD about Sony's A-Mount, and I find it a peculiar spin to put on a company supporting current technology while it pushes the market forward with innovations. I find nothing mysterious or incomprehensible about Sony's strategy: it seems to me that they perceive this to be a transitional stage in the photographic imaging industry and they want to have matured product lines to cover multiple eventualities; they have product to cover everything from cellphone cameras to a rumored medium-format fixed-lens RX-series model. Pretty straightforward to me: cover all bases; and it inspires no less confidence in this photographer than the paint-ourselves-into-a-corner strategy that Pentax seems to have been committed to for years.
According to the gear list in your signature, you're still shooting with a K-5, and there's no reason why you shouldn't: it's a great camera and nothing I own today comes close to being as much of a pleasure to use as was my K-5. It serves as proof, as if any was needed, that people can keep using a camera body for years. Sony has yet to even develop a Full-Frame sensor that will outresolve my Zeiss Planar 85mm f/1.4 or Sonnar 135mm f/1.8; If Sony abandoned Alpha-Mount tomorrow, I'd still be using the a900 and a99 with the aforementioned lenses, as well as the 70-200mm f/2.8 G (which isn't stellar but still better than the equivalent K-Mount Sigma I once used), and the Sigma 35mm f/1.4 ART for years to come. And even that "risk factor" is mitigated by the rumors of an A-Mount/E-Mount hybrid body that one hears every now and again.
Had I been too "worried" about the future of A-Mount to buy into the Sony system, I'd have missed two years of shooting with the system that suits my needs. And I'd still be jumping with anticipation at every rumor that Pentax was finally going to release a full-frame body.
I don't get paid to be a market analyst, and market analysis just not something I care to do for recreation. After a while, I was no longer appeased by armchair analysis meant to explain why Pentax can't/won't/mustn't make the products I need, or the ones I want. I stopped wishing that Pentax would make the advanced compact/mirrorless ILC body/full-frame camera I wanted and started choosing among what already existed. So, I found my full-frame needs satisfied elsewhere, and had my desire for compact, lightweight ASP-C format cameras satisfied by Fuji (in the form of the X-E1) and the Ricoh GR. I decided to place the priority on getting what will suit my needs today instead of sitting back and speculating on its eventual obsolescence.
And besides, are you really going to characterize investment in the Sony system as risky when you are [perhaps exclusively] invested in a system made by a company whose parent ownership has changed twice in 5 years and which now exists only as a brand? Pick your cliche: glass houses and stones; pots and kettles...
-XM