I'm new to AP also. We expect to go three times this year, and so I'm confident it was worth it. I think it would be for two trips in a year also, but I'm not sure about the dining.
On our second trip, we saved a bunch of money with the AP because we want to stay in two different hotels in the week so we couldn't use the 4/3 plan. For our December trip, though, we ended up booking with the 4/3 deal as it was a better deal on hotels even with the AP discount. I didn't use the the Park Tickets, though, se we can apply them to our AP renewal or use them another time, so it was still a good investment.
We never get dining plan, so that might make a big difference. For room and ticket prices, AP has been a good deal for us. You're right to do the research on that one.
Happy planning.