I have been quite satisfied with my current crop if lenses until recently. The 40-150 mm has given me enough reach for my typical shooting style (primarily travel and landscape) and I have been considering making the investment in the newer f/2.8 PRO tele zoom. However, a job last weekend shooting a stage production in which I just couldn't get as close to the performers as I wanted has caused a rethink. The effective 300 mm (FF) throw of the 40-150 just wasn't enough. I made do by cropping but prefer not to have to do that. With the above in mind, I have been considering a longer zoom. Olympus has the 75-300mm and Panasonic the 100-300mm. The panny is significantly heavier than the Oly due to the in-lens OS system. That is a definite factor since I have been actively trying to CUT weight and bulk in my bag as I get older and more arthritic. On the other hand, the Panny is faster at both ends of the zoom. I see the "II" version of the Oly M.Zuiko at B&H for $549.00, which is only about $50.00 more than the Panny so price is pretty much a wash. What are the opinions of members who have shot them of these two lenses? Are there any significant differences in IQ or other factors I should consider?