On average it'll take you about 3 days to find a share at current sharechain difficulty (770k). That means there will be dry periods much longer, and probably some days it's shorter.
How about you drop the obvious bias? "Will" be dry periods, and "probably" some days its shorter? Seriously?
There WILL be longer dry periods and there WILL be shorter dry periods. That is the nature of variance. But when your total hash rate translates to $2/day the absolute variance will not be much. You will NEVER underperform by more than $2/day.
Another factor regularly overlooked with p2pool is the high reject rate. I know I was extremely disappointed when those 3 or 4 days would go by and I'd finally get that cherished share ... only to have it rejected.
If you have a "high" reject rate then something is malfunctioning or misconfigured. A few percent or so rejects is normal and anything up to about 10% probably does not hurt your earnings relative to another pool.
I tend to think you won't be getting $5 or $10 every few days with 12gh/s.
Then you would be wrong. If your expected earnings are $2/day and you have multiple days of getting $0 then you WILL also have days of getting $6 or more. Mathematical certainty.
Over periods of weeks you will very likely earn more than regular pools even with 12 GH. If you want to earn less, go right ahead, but stop spreading biased misinformation.