I have used the JL Slash series as well as the RF power series. All of them are great amps with nice power and clean sound. I now have a 450/4 over a t8004 and they both have excellent SQ - so I imagine that the 300/4 and 25 to Life are comparable.
You cannot go wrong with either. I do like how the RF Power Series have fuses onboard.
Neither amp has a bandpass filter to run your comps active, so that is no advantage. Both should be about as clean. The RF is a power amp, not a punch - the punches are kind of substandard to some 4 channels.
I would probably go with the 25 to life because it is 1 ohm stable on all 5 channels (might even go .7 on the 5th with solid electrical - think future) for more sub configurations and a single hookup. The 25 to life will also do about 100W at 2 ohms if you run your comps active, which is about 25 more watts. The 900-1000W out the 5th channel is an advantage as well. Also, less room in your sled.
Rest assured that you will do well no matter what you choose.