No need!
I vote Marathon!
I have noticed that Marathon seriously skews the gameplay, though. I mean, I
enjoy the results, but there are substantial differences from Epic, more so, to my mind, that between Epic and Normal.
Obviously, as many maintain, Marathon is a speed for warmongers. It takes longer to develop the techs for and to build newer, more advanced units, but your existing ones move at the same speed, so you can war with your ancient/classical/medieval/renaissance/modern-era army for many, many more turns.
This tends to result in domination or conquest wins for me. Actually, in about a half-dozen marathon games I've played to completion, I've only ever won by domination. I can't imagine trying to win by culture or space race at this speed. I also tend to end the game much, much earlier, with world domination occurring, on average, in the 1700s rather than the late 1800s/early 1900s as in an Epic-speed dom win.
The other thing that happens is that on Marathon speed, a backward civ gets extremely backward in a relatively short time and stays there. With the increased research time and the warmongering advantages mentioned above, the merest sliver of a tech lead tends to snowball, while the tech laggards find it harder and harder to catch up. So there's another reason it's a warmonger's speed: not only do you get more use out of your army, if you play your cards right, there are a bunch of sitting ducks on the map.
So as much as I enjoy marauding around the map with Praetorians for hundreds to turns, I don't know if I'll adopt Marathon for a game... maybe not until I play a Rome ALC, since it really gives Praets a chance to shine.