I was in Tokyo over the weekend and popped into a camera store where they had a bunch of new stuff, including the mini Panasonic 35-100 (complements the 12-32 the GM1 comes bundled with). Size/weight: Amazing. Incredible. Wow. Super. Seriously...a 70-200 equiv in a package that small? Nothing but praise for it. It's also very light...it's a traveler's dream. Construction/feel: Felt nice and solid, no barrel play, etc. I've been reading that it's made of metal, but I don't know...if it is, it's rather cheap metal. It certainly doesn't feel like the O75, for example (I know, not the same price category either, but when people think metal, they think O75, Leica, Voigtlander, etc...it's not like that). The silver actually looked rather cheap and plasticky. It definitely wasn't a visually impressive lens. The black is much, much better looking, in my opinion. Otherwise, the lens felt fine, but the zoom ring on both was a little clunky/sticky. It didn't zoom nearly as smoothly as I expect my lenses to. Performance: This is a very, very, VERY unscientific test. I shot a few frames in a store and that's it. I handheld it in less than optimal lighting, so there's certainly room for error...on the other hand, it was a very real-world test, if you shoot at night, indoors, etc. I also had my O45 to compare it to. At 45mm the 35-100 is incredible. It's juuuust about up there with the O45. It's sharp and contrasty, with great colours. CA seemed to be completely absent. No complaints, would use it in a heartbeat in just about any situation. At 100mm, however, it was a different story. For one, at 100mm, you're down to f5.6, which is starting to be painfully slow. Even with stabilization (which the lens has), indoors at 5.6 you're going to be cranking up the ISOs at 200mm equivalent. There also seemed to be a dramatic and immediately noticeable (even on my LCD) drop in sharpness and especially contrast. Black letters on white signs turned to grey, sharp outlines turned mushy. I was blown away by the performance at 45mm, but left wanting more at 100mm. Price: Here's the big one. I love this system, and lately I've been suffering from a severe attack of G.A.S. Its unimpressive (to me) performance at 100mm notwithstanding, I was ready to buy it. I figured this with the 9-18 would make for a killer super light/super small package. I also thought that the performance at 100mm would likely be much better outdoors with more/better light. But...it was going to be around 42,000 yen ($420, give or take). Or...about 20% less than the Panasonic 100-300 (sitting next to it on the shelf, I know that prices in other places vary), or as much as a pristine used Panasonic 100-300. And THAT was my big stumbling block. Yes...the 100-300 is massive by comparison, but it gives you significantly more reach (12x effective magnification vs. 4x), it's a stop faster at 100mm and is a proven good performer. As much as I wanted a small, light lens to add to my kit, I just couldn't justify the price. Perhaps when it becomes available as part of a GM1/5 kit, it'll be a much better bang for the buck. At that time, I'll likely be on the lookout for it and buy one separated from a kit. Until then, I think the extra size/weight of the 100-300 (which is tiny by supertelephoto standards) is worth it for the extra stop and reach. Again...disclaimer...this is not a scientific test, just hoping to help out those of you who may not have access to this lens yet.