Generally I've been doing ok with the bag. I've got to about 6 or 7 inches now, and I like the way it's turning out. However, I have noticed that I have a tenancy to lose my concentration a little, and maybe make mistakes such as doing a row of the wrong kind of decrease, and this generally coincides with when my housemate is talking to me ;o)
I've decided though just to go with whatever mistakes I make, unless I start to lose stitches. It's only a bag, and it doesn't look that bad after all.