I'll throw in my 2 cents.
I've used AFF and AM in the past.
I used AFF when it was fairly new. Met a few people through there. Then I started getting unsolicited messages from super hot women asking me to write back. It seemed pretty shady.
So I moved on to AM.
Met a couple of people through there as well. Still see one, occasionally. Then, I started to get messages from super hot women asking me to write back.
Hmm.
While both of these services were legit to start off, once they built up a base they turned into scams pretty quickly IMHO. Ditto for Lavalife.
I wouldn't pay, when Plenty of Fish is free.
There's a big difference between the two experiences for me.
I was looking for a long term affair on AM and AFF. SP's are great, but expensive. I found a couple and had some great times. As circumstances changed, we went our seperate directions.
We all know what the advantages of SP's are so I won't bore you with my take on it. Just realize if you're going on AFF or AM to meet someone right away and get lucky, you're mistaken. I never met anyone that didn't require a "get to know" period first. Which, with the right person, can be fun as well. One of them called it "new relationship energy", which is pretty accurate.
My 2 cents. Take it or leave it. If you search for
Ashley Madison I posted more on my experience as well.