I have an E-1 and E-3 as the SLR compliment to the M8. I use the E things for macro, tele, accurate framing and ultra wide angle. Next to the M8, the E-3 is complexity, with all the options and frills like Live View. I consider the 4/3rds advantages to be the lenses, dust buster, color palets and weather proofing. I also like the ability to use legacy lenses from many mfrs. I suppose one downside, for me, is the size (about Nikon F2 size & weight), having gotten used to the M size again. I have used the system since Oct. 2003 and haven't run into any sever limitations, for my hobbiest uses. The 100% view finder on the E-3 is really nice as i the IS. The interface can be.....
.........when compare to the 1½ menus of the M8. I do my hi ISO work with the M8 so I haven't run into any of the reported problems in that area.
Rugged, weather proof, built from ground up in the digital metaphor, works for me.
Bob