I was planning to bottle my beer before leaving for a trip, but my friends being here distracted me and I totally forgot about it until today. I moved it to the bottling bucket and drew off a sample and it looks, smells, and tastes fine, however I am wondering what kind of a change a month of sitting in the wort can cause, purely from a curiosity standpoint.
It's my first time with this particular kit so I can't tell specific taste changes myself.
An extra month of aging isn't a problem for a beer with healthy yeast stored at an appropriate temperature. It might have been better if it was already bottled, but your yeast have had extra time to eat up residual sugars that tend to make home brew a little heavy, and the yeast should have flocculated more giving a cleaner, clearer beer.
The potential downsides are yeast autolysis, if it is stored too warm. And hops flavor will decrease, but that might not be very noticable in an irish stout.
I have left beer in primary for over a month due to travel, etc. to no ill effects (assuming proper sanitation - problems will be more apparent given more time to infect).
The only issue you may have is while the since the yeast flocculates and can be clearer, much of it will drop out of the wort into the trub.
If you are bottle priming, this can cause carbonation to take much longer than usual. I have had it take months.
Priming can be sped up by agitating the closed bottles gently from time to time (semi-daily). Alternatively, you can help things out by simply sprinkling dry yeast (of the same type used in primary!) into the priming bucket to make sure sufficient yeast is present. I have also read about using champagne yeast for priming, but opinions seem to be be mixed