Like the title says, this is a mastery vs int question. Now, i know the main difference between them, int increases spell power and crit, and mastery inc direct heals, which in turn inc hots. But, why stack mastery (for gems really), instead of stacking int, which also increases crit (although not by a big margin). What would be the difference in having 20k spell power and say 30% mastery, or having 25k spell power and say 20% mastery?

Im not sure what it is, but i see a lot of druids with around 25k spell power marker, maybe little less, and lower mastery. I went the route of getting 3043 haste cap, and "stacking" mastery, and have 23k spell power and 30% mastery (raid buff with food).

Any info would be great, thanks ahead of time.