Opinions on mana regen runes

I have been experimenting with mana regen runes now i have a question for you guys which would you consider more seals or glyphs now i know that seals give more but on top of the mana regen you are getting what are you losing out on the stats that you're losing would it be more worth on seals or glyphs? second off how much mana regen I mean I have saw 2 mana regen 3 mana regen and even 1 mana regen my question is how much is too much to where you lose too much of your other stats? What I am currently doing is 2 mana regen in seals for my supports who need it ie: karma and nami