See if you can go out and shoot both. Buy whichever one shoots the best. You will shoot thousands if not $10,000+ worth of ammo through them before anything should go wrong.

For what it's worth the S&W N frame comes in 44 Mag. Ruger just introduced the GP100 in 44 and it is limited to 44 Special...

The most likely weakness of he model 28 is that the cylinder is so large that an excessive amount of rapid fire can result in damage to the cylinder stop and notches.