Just check Pacers game, with m2m i bet he was going to win that game, the 2-3 dind't really help him.
In general I'm not fan of 2-3 zone, but with man to man he would lost much more in this case.
1) with 2-3 zone there were significant decrease in number of shots of my PF/C, with M2M his bigmen would have been probably fouled out before the start of the last quarter as they tend to foul very much
2) he would have had much trouble with my guards layups, but he would have less trouble with SG jump shots
3) with the same lineup he would be destoyed by jump shots of my SF
4) with different lineup he would loose much more on rebounds and also he would lost some power on attack