I own an OM-D E-M5 with kit lens 12-50 and a 40-150. I'm in the market for a fast zoom. I'm ready to buy the Pany 12-35mm f2.8. But, there's the rumored Oly fast zoom mentioned at 43rumors.com (FT4) Coming within 2013: Olympus f/2.8 fast zooms similar to the Panasonic X. | 43 Rumors that's supposed to (61-80% chance) come out this spring/summer. Would you buy the Pany now or wait for the (rumored) Oly fast zoom?