people seem to think it gives more. I played 2 games just now

20 minute win on SR = 76 ip
25 minute win on dominion = 73 ip

In the time you play 1-2 rounds os SR, I can finish 3 Doms.

apparently not always since my dominion match took 5 minutes longer

However the scaling for them is somewhat different as the longer you go on SR the returns for IP diminish. A usual game of Dominion is somewhere around 18 min and so you could probably fit two Dominions in a normal SR match (not considering some occasional 20 min wins, as that isn't as common as 40 min matchs). From memory you get something like 115 IP from an SR match that long and 118 from two Dominion matches that long. So it doesn't make a huge difference.

duh and/or HELLO!

ITT: All summoner SR games are 20 minute surrenders.

25 minutes is a long game of Dominion mate. 20 is the shortest possible SR win.

Over time it does. SR times are inconsistent, averaging 30-45 but as quick as 10 and can go well over an hour.

With dominion, you'll get through more games in the long run.

that was a very good story. i guess you should not play dominion anymore. i see you are a gold player. that means you're one of the elite players in this game. being an elite player, i know you must know ip points are what separate the good from the great. some people might say you play the game for fun, but those are the losers, right? if you can get that extra 3 ip at the cost of missing out on a fun new game, you gotta take that 3 ip, right? yep, that's the secret to getting on top.

Nail-biters in Dominion go up to 27 minutes. They're about as frequent as 80-minute SR games.
On average, things balance out. Short Dominion games are short. 7:30-10 min short. I think the IP gain is fairly consistent across large periods of play, though there is the disadvantage of sitting through more champion select screens :P