Originally Posted by dyqik
but you'll be undercarbed compared to typical bottles, even for English styles.
I would agree. I do have one of the rigid pressure barrels and only use it on a style were taking the hit on carbonation is acceptable. The co2 cartridge won't really help this much, the big advantage of the co2 in these barrels is it allows you to keep a positive pressure above the beer. Without it, pouring off more than a pint or two a day results in a loss of pressure in the barrel and the tap slowing to a very, very slow rate - almost stopping sometimes.
The other issue is that these pour very foamy with what little carbonation they can achieve. This is not a problem for a single pint, you just keep the tap on low and it almost gives an effect like a beer engine - great for English styles. But for trying to fill a number of bottles - you would need the patience of a saint!