I don't like to use the "rub their nose in it" method myself.
First off, I'd take her in to the vet to see if she has an infection. Peeing outside of the box is frequently a sign of a UTI and shouldn't be ignored.
If a vet visit finds no UTI, then look at external factors. Has something changed at home? Even minor things? Peeing outside of the box can also be a sign of stress or an upset kitty. I know our Skye tends to chew on things and make messes around his box instead of in it when he's upset.
Third, how many boxes do you have and how often do you clean it/them? It could be that she's becoming picky about her litterbox. We used to have 3 boxes and even at that Skye would frequently go outside of the box. When we replaced them with two littermaid megas, we almost never have a problem any more.
If you've established that she doesn't have a UTI and nothing has changed so she doesn't seem stressed, it could be worth trying the littermaid. The pros are that it does leave a clean box almost all the time and it's easier to clean out. I think it may also use less litter in the long run. But the cons are if you have a cat who likes to DIG, she may not like the littermaids be cause they only have a little litter in them. And it's harder to monitor the health of your kitty with the littermaid.
We went with the littermaid megas because the regular size wasn't large enough for our big cats, let alone 2 full-grown and 2 kittens who will become as large as our adults. DH did some research and found the littermaid mega to be the best option for us, and it had an excellent safety record.