I really like the value you get with the JBL equipment. I also really like the styling you get with the JBL over the fosgate. I am using a 600.1 to power two JL 12w3vsd4s and I love it.
the RF class AB amp will draw more current and produce more heat per watt, but will generally be a cleaner amplifier for those downsides. Now you do want to be sure that RF amp has a LPF and infrasonic filter both if you choose to go that route for a sub amp. otherwise you need to use external filters for both purposes.