My observation...
Most consumers in the market for a camera suffer from the "gotta have that spec" syndrome. Rather than really take a look and analyze their needs, they get stuck drooling over dxomark results and keep thinking.. I gotta have this or that based on measured numbers.
Of course, you will not get 100% the capabilities of a DSLR in a micro 4/3rds camera. But you also won't get 100% the shooting experience of a micro 4/3rds from a DSLR. Everything has advantages and disadvantages... as well as compromises. If squeezing every ounce of ISO performance and dynamic range is an absolute high priority, then its time to deal with the weight and stick to a DSLR.
I went from a Canon 1dmarkII and Canon 5D with 8 L primes and zooms (enjoyed it semi-professional too). I purchased a used first gen micro 4/3rds panasonic G1 with the intent of keeping the Canon system. Around here in the TPF, I was probably one of the first to shoot with one. The G1 is ranked about 50% of the OMD E-M5 numbers via dxomark and a fraction of what the Canon's are capable. Its a lowly first generation product. Surprisingly, in my world all those specs and numbers didn't matter much in my real world use. My life changed naturally. I no longer nor have any intent to shoot professionally.. I have 3 young children.. I love to walk about (hike) and have always carried a camera with me.. its a part of who I am. Simply put, the micro 4/3rds is an ideal blend... My entire system fits in a should bag that is 1/4th the size and weight of DSLR system. Its no longer a conflict of priorities in life but rather photography blended into my life. I shoot just as much as I did when I was single... and that's what is important.
Think about priorities and examine your expectations... its a personal decision.
After much thought, I sold the Canon gear that was gathering dust and expanded my favorite system (Leica M) and paired it off with a rather nice micro 4/3rds system. No regrets. Prices of lenses AND availabability is pretty favorable too. I stress, this is my experience and I don't recommend micro 4/3rds blindly to everyone that asks. It is not the system for everyone and for many it is a system to compliment a DSLR system. "A lighter weight alternative when the professional needs a break." I recall PMing someone a while back.
Comments about shooting with micro 4/3rds OMD E-M5 and a E-PL1.
* E-M5 cannot track worth crap. PDAF will not satisfy the sports shooter. The good news is that single point focus in non-continuous mode is lightning fast. Faster than anything I have ever shot. I used to default to my Canon but now I pump focus and spend a little time thinking ahead of the action like I should. Not ideal but I don't shoot sports often.
* Lens availability is awesome. Prices are reasonable.
Four Thirds | Four Thirds | Micro Four Thirds | Chart(Lenses).
* Fast telephotos primes are still yet to come.
* With two manufacturers, Olympus and Pansonic there are so many camera bodies to choose from.
* Not only are the bodies small but people forget that the lenses are small too. One of the advantages of a 2x sensor crop. Not too big not too small. My 12-35 f/2.8, 35-100 f/2.8, and 100-300mm all weigh a fraction of the Canon equivalents. I know of no APS or FF 600mm (exclude mirror reflex) lens that is the size of either the panasonic 100-300mm or Olympus 75-300mm. Along with those, I also enjoy 20mm f/1.7, 12mm f/2 and 45mm f/1.8 Each of those sized similar but lighter than my Leica M glass.
I now shoot 50/50 FF (Leica )and MFT. Some samples:
I also consider the other mirrorless systems. Each are impressive offerings especially the Sony RX1 (fixed lens). Fuji would by my next choice. Many on paper offer a bit more dynamic range and ISO performance than the micro 4/3rds. But the double edged sword is the size of the optics, price and availability. Interestingly enough, sheer frames shot... my P&S still win. I guess I find that even micro 4/3rds isn't small enough. Recently replaced my aging old Panny TZ5 with a Sony WX300.. not too bad.
