What is everyone's opinion on the different rune abilities. im refering to if you think it's better to get more Flat effect runes (runes that do the same bonus regardless of level) or /LVL runes (runes that give a certain bonus per level)

it makes sense to me to go with mostly /lvl ones, because most of the /lvl runes end up having larger bonuses at level 18. and by end game, when most competitve games are won, most, if not all the players are at 18. so if your runes gives you +2 @ 18, whereas your opponent has +1.8 since lvl 1, wouldnt that give you an obvious advantage?

the only thing that i think i'd use the flat runes for is probably HP or MP. these are the stats you're mostly gonna want to be bigger than early game, to scoop an early gank or 2 and put you ahead. all the other stats you'd want the advantage late game, i'd think. maybe its just me... haha

Opinionsss??

Depends on what you're going for IMO, and the fact that there are some types that only come in flat as far as I'm aware of (i.e. +crit runes). Many types of x/lvl runes = the flat effect runes by about level 5, so for those i'd always have to say get the x/lvl runes. I personally get x/lvl for everything I can, except my summoner level is only 17, and thus from the combiner I've managed to net a few tier3 runes I can use and I of course use those where I can. A friend of mine uses all flat +armor/+Magic resist runes and some +health runes so that his early game is more effective and he doesn't die so much.

flat hp quint runes are rigged, so def use those.
for blues, level mp runes are good.

In particular, HP is one of the easiest to explain while sometimes flat is more effective. An additional 40 flat is greater than 50 (as it is at the moment), or even if it was increased to 80, late game. Because 80 late game is an additional hit (because everyone is so much stronger), while 40 early game is 2 hits and makes you less squishy to ganks and people less brave (in a mind game sort of way).

Also, when I watch the livestreams, most of the games last 25 minutes. So the big battles happen early early, aka beginning of the game.