For a while I have been thinking of going over fully to MFT.
I'm using the E-PL1 with zooms covering 9 - 150, which is excellent coverage and provides very good images.
With the E-M5 and ever more fast primes becoming available, from various manufacturers, I'm considering switching from the 4/3rds top-pro zoom lenses to achive a similar the Image Quality
Using an analysis program (ExposurePlot) on my image files, I could achieve a similar coverage of my 4/3rds kit with MFT primes selected from the focal length most used. I'd just have to move back & forth a bit more.
With the OM-D and 4 fast primes the kit would look remarkably similar to my OM4ti kit and would be of very similar size, and a bit lighter...
Ian very kindly let me use his 12mm (London walkabout) so I'm aware of the IQ that produces. His latest portraits are clear evidence of the IQ available from the 45mm and everyone raves over the Pany 20mm. With a 75mm f/1.8 on the cards, this may well be my future kit.
While zooms are so useful and my 14-35 f/2.0 is excellent, the weight advantage of the MFT is hard to ignore.
Very much looking forward to seeing just how good the E-M5 is in real world situations.