Another important thing to keep in mind is this:
Almost everyone wants smth to be finished ASAP. If a developing group listens to thouse who want a product to be released ASAP, the product would suck. If you ever see someone telling you "OMFG JEEZZUSS HERPY-DA-DERPY CHRIST, RELEASE THE SHIT ALREADYZ" - don't listen to them. If you are aiming to release a product ASAP without even testing it propertly, no doubt it would suck.
For example - Half-Life 2, EP 1 and 2 are f*cking awesome games because Valve's staff are smart enough not to listen to HERPY-DERPY kids whom want shit to be released immediately.
So, take your time developing the mod. If your group is mostly busy in life and if there's little free time - use it with patience. This would probably take a lot of time to get a product finished - but it's a good way to make an awesome, stable, game/mod or w/e than rushing everything.
Good luck,
LaS3r