Bottling from keg, how long?

There is probably a sticky thread for this, but couldn't find one.

I am brewing several batches of beer for the holidays and will be giving alot out as gifts. I'd like to keg the beer and then fill the bottles, therefore removing any sediment so that when people go to drink them they won't have to know how to pour them or anything.

I have a beer gun (never used) and I'm wondering how long the beer will stay good once it's in the bottle (i.e. flavor and carbonation). Or am I better off just bottling it all, would that be easier?

 

I only use my beergun if the beers will be consumed within a week. I find that the carbonation is not the same as bottle conditioned beer. I will also be giving out beer as gifts this season but they will be bottle conditioned.