I have the spent the better part of my photographic blogging career complaining about Micro 4/3. I bought into the system with the Panasonic GF1, a brilliant camera, and then spent the next three years being disappointed. The lenses implied by the existence of the GF1 never materialized. The future cameras implied by the existence of the GF1 were never born. We finally got a wan follow-up in the form of the GX1, but by then, the market had moved on significantly, leaving Panasonic in the dust.
But now, in a come-from-behind surprise, Olympus has produced the first true follow-up to the GF1, the E-M5. I've used it for a short time, and while it's not everything for which I could have hoped, it is most of it. ISO performance is great, operational speed is excellent, the body feels great, and the video performance is surprisingly good. I think that it's a bit pricey, but beyond that, it's a very solid product.
The real excitement, though, has nothing to do with the E-M5 or any possible aspects to the upcoming GH3. The real action is in lenses. Olympus finally, finally, released lenses worthy of attention with the 45mm and 12mm. Then they announced a 75mm f/1.8, and even at $900, it's a bargain. Panasonic, not to be outdone, and after much... anticipation(?)... finally released their long-known-about X Lenses that don't suck (the first two X lenses, the 14-42mm and the 45-175mm were underwhelming).
Since these cameras and lenses will likely be used as secondary camera for people who already own full-format gear, when a lens costs that much, it becomes a question of whether the person would rather invest that money into more FF lenses. That possible problem aside, I know that I will be willing to pay the price, and if we use me as an experimental sample and generalize out into the US market, 100% of the population wants to buy this lens. That's impressive.
Micro 4/3 just got real exciting real quick. I want both Panasonic X-lenses. I want the Olympus 75mm. I want the SLR Magic Hyperprime 17.5mm. I need to start saving.