Two physicians will get you, at a minimum, three, usually contradictory, bits of advice.
I am in a two man single specialy group, every other neph in the area is solo.
for me, having a partner is a blessing, even though we are very different.
I personally would balk at being in a large group: just that many more personalities to deal with.
Upside: some one to cover for you, potential more time off, shared overhead.
Downsides include cooks in the kitched warning, HAVING to get along with other physician(s), loss of control.
I guess you need to ask yourself: what is it I am looking for in this change?
Good luck.