Honestly i think the people who make the game need something like 5 days instead of 3.

just saying..

I highly prefers 7 days jams over 48 or 72h ones.

In a 7 days jam I can spend 1 or 2 days trying new stuff (graphical styles, gameplay, technologies) and make a good game, original and well polished. This makes for a better learning experience and better end product.

My 2/3 days jams ended up with half playable prototypes, and me not learning much.

I agree. If you get more time its better because making a bad game in a short time is worse than making a good game in a long time.

I agree, I reckon 7 day jams are ideal. Gives you a chance to space it out by working on it a few hours each day. Great if you have a full time job and/or family commitments.

Meh I only have about 2 days to do mine... Damn job getting in the way... 

I prefer short jams anyhow... Keeps the mind focused and is a great exercise in both time management and the art of descoping.