I like these cameras for a number of reasons.
- Light-weight. Even with a small prime mounted on the body (or a slightly larger zoom), the mirrorless cameras are the smallest and lightest capable interchangeable lens cameras I've ever owned. I can wear one around my neck all day long, and I've even forgotten they're hanging around my neck for the most part.
- Affordable. With the notable exception of the E-P2 (which I purchased as a kit with the M.Zuiko 14-42mm and VF-2 electronic finder), all of these cameras have been purchased for 'mere' hundreds of dollars. The E-PL1, the least expensive of the lot, dropped down at one point to $150 for the body. The E-PL2 dropped down to $200. Prices have drifted back up on both recently, and we are talking about cameras that've been discontinued, but still. Inexpensive yet quite functional. Even if the sensor is a 'mere' 12MP 4:3rds size.
- Unobtrusive. Just like they're so light weight you can forget you're even carrying one, the camera is small enough to blend into the environment. That is, unless you're behavior is obtrusive and gives you away. But the camera certainly won't, unlike the larger DSLR cameras like my E-1 or E-3, which will almost always garner looks my way.
- Fun to use. Heavy use of automation (and depending upon it) combined with low cost and light weight make today's mirrorless cameras fun to use. It may gall some to think they're reduced to what they consider the equivalent to point and shoot, but perhaps if we all spent more time on the scene before us and less on the camera we're trying to use we'd produce more art. Unless you do something really strange, you're guaranteed technically correct (exposed, focused) photos. Whether they're artistic masterpieces or not will be open to broad interpretation. But if art is what you're after, then the camera can get our of your way ("transparency", I've heard it called) to your art. And I've certainly seen plenty of excellent art from others using these class of cameras.
Light-weight. Affordable. Unobtrusive. Fun to use.
Super-high ISO? Ultra-fast and ultra-expensive lenses? Obscure features? Anything beyond the four reasons I outlined above becomes almost irrelevant and begins reducing photography to a grinding job instead of a joy.
One other comment.
I've grown tired reading endless complaints about the so-called lack of controls on these cameras. Direct controls for aperture, shutter speed, ISO (including compensation), etc, etc, etc. We had those controls on film cameras because we had no choice. We set our film's ASA on one dial, then selected an aperture and shutter speed via other controls based on the measured light level and the film's ASA to make a decent exposure we could work with in the dark room. While I certainly enjoy such controls when they're there (see Olympus E-M5), I no longer need those types of controls festooned to the camera exterior. Mirrorless cameras have stripped away everything superfluous, down to a minimalist essence for creating photographs. Small, extremely compact, with large enough sensors. Something that doesn't stick out like a sore thumb the way the much larger, heavier, and expensive DSLRs do today.
I'm truly done with the DSLR. There are very many who still feel there is a place for the DSLR, especially in their work, and I certainly respect that. This is all about me. I still keep an E-1 because I love the way it was made, and as a reminder of what I've moved beyond. Whenever I get the urge to buy a big DSLR I go and hold the E-1 for a while. That seems to be more than enough to satisfy the urge. I've put my money where my mouth is by buying into the modern mirrorless revolution. I hope it continues on. I know I'll continue to buy and use them for as along as I can.