Sorry, but I've no haiku to offer.
My first job out of residency was a single hospital democratic group with a two year qualification and then a two year "buy in" period. After that, all partners are equal.
My current full time gig is with California Emergency Physicians, the largest democratic EM group in California (and maybe the country). We currently hold 52 contracts. There's a long gradual vest to full partner over 5 years.
The advantage is that "The Man" isn't skimming profits off of your hard work, a voice in the direction that the group handles medicine, and usually better relations with the rest of the medical staff.
The disadvantages are few IMHO. You are expected to participate more in medical staff activities (committees and whatnot). Working for "The Man" (i.e. contract management groups) is less hassle when it goes smoothly. Just go in, do your shifts, and go home. The problem is when it doesn't go well. And CMGs will generally pay you less than a democratic group.
My part-time job is with EmCare, which in my experience, is among the more benign CMGs. Though my experience with them so far is pretty short (less than one year), I have some friends who seem pretty happy working for them.