OK, so I just saw this episode for the first time, (what else is new) and I must say I was pleasantly surprised... Not only was it a good, original story, but I actually laughed a few times... Like when Spongebob yelled: "Hey I'm talking grandma!" and the old lady was like: "...Oh..."
Or when Spongebob said: "OK, that didn't work at all..."
Spongebob wasn't too annoying, but he was also very passionate about his job, (something that gets lost in some of the newer episode...)
So, I gotta go with... 7.5/10!