As far as I know, if MS Sans Serif is not available on your mac (which is normal) it will not behave better than Pages.
M…oSoft itself dropped MS Sans Serif in Windows Seven.
If you search on the net, you will find sites offering the named font but, as they required a registration I didn't downloaded it.
Here are quite every monospaced fonts which I installed here.
Maybe you will be interested by some of them :
Andale Mono (659 glyphs)
AurulentSansMono-Regular (267 glyphs)
Consolas (2731 glyphs)
DejaVu Sans Mono (3161 glyphs)
Droid Sans Mono (612 glyphs)
Free Monospaced (2576 glyphs)
Latin Modern Mono 10 Regular (740 glyphs)
Latin Modern Mono Light 10 Regular (740 glyphs)
Latin Modern Mono Light Cond 10 Regular (740 glyphs)
Liberation Mono (663 glyphs)
Menlo Regular (3157 glyphs)
monofur (675 glyphs)
Monoxil (275 glyphs)
OCR A Std (270 glyphs)
Prestige Elite Std (374 glyphs)
TeX Gyre Cursor (1242 glyphs)
Tiger (1388 glyphs)
Tiger Expert (1172 glyphs)
Verily Serif Mono (244 glyphs)
Yvan KOENIG (VALLAURIS, France) dimanche 26 février 2012
iMac 21”5, i7, 2.8 GHz, 12 Gbytes, 1 Tbytes, mac OS X 10.6.8 and 10.7.3
My Box account is : http://www.box.com/s/00qnssoyeq2xvc22ra4k