EGICN,
I think you've got your terminology a little off.
A Vmod is atually the brand name of a popular bottom feeder made by vapage. It's a piece of hardware.
A Mod is usually a small tube or box that houses a bigger battery than you would normally see on an electronic cigarette.
I think you are asking about an Ego type device, or more specifically an ego or ego twist. the mAh just says how long the battery will last roughly before you have to charge it.
Most people use a 650, 900 or 1000 mAh. A 1000mAh is going to be kinda long.
For comparison, a 1000mAh ego twist is approx 5 inches long before you put a carto or clearo on it which will add another 2-2.5 inches.
An ego twist 650mAh is about 3-3/4" long.
a 650mAh will last about 4-5-6 hours until you need a charge, depending on how much you vape and what resistance you are using
a 1000mAh will last about 8-9-10 hours.
Obviously, if you want to vape longer w/out a charge, you have to have a longer or bigger battery right?
Otherwise, it's a personal choice. a 650mAh is better size for pocket, but I carry mine on a lanyard or in purse so I have a 1000mAh....I hate charging!
Hope that helps.
I just ressurected this neat old topic, "A side by side comparison of ecigs and mods" from 2010. There is more equipment available now, but it's got some pretty NEAT photos, I thought it should be ressurected.
Here:
http://www.e-cigarette-forum.com/fo...n/78628-side-side-comparison-e-cigs-mods.html
I've been on ECF for 5 months and never seen it before. Wish I had! You never know what treasures you're gonna find here if you read dilligently!