To be honest, I think one of the reasons people are so divided on who's voice is better is because everyone's Shepards probably look much different from one another. Mark Meer's voice goes very well with my canon paragon Shepard, and I credit that to my Shepard unintentionally looking like Jon Cryer, and as such I almost expect said Shepard to come off as slightly meek but still badass, and Meer fits completely. I can actually say the same about my non-canon female renegade Shepard (she doesn't look like Jon Cryer though, thank god). I think it's more-or-less just the way I designed and play my Shepards that makes their voices fit.
It's funny really, I tried playing through with a second male paragon Shepard, only this time I intentionally made that Shepard to look middle-eastern; voice did NOT fit AT ALL, and I abandoned that Shepard on the first Citadel visit because I just couldn't take it. This Shepard and my original Shepard were saying the same lines, but the new one's appearance and voice clashed immensely.