I have a set of RXE's, and I consider them the best value in a pedal today in terms of dollars-per-gram (mine weighed 258 grams/pr. + 50g each cleat including the bolts), the size of the platform (I don't get hot spots like I did with Campy pedals), low stack height, and overall function. The RX-series are the best road pedals TIME as ever made, IMHO.
Also nice to have is the in/out "Q" adjustment. Since I have wider feet and the inside of my shoes rub on the crankarms with the 'inside' setting, I have to mount the cleats to the 'outside' position on my FSA Team Pro Issue crankset. With different cranks perhaps I could set them to the 'inside' for 2.5mm narrower Q factor.
The standard float range is fine for me and I don't want for any adjustments there. YMMV.
I have had the left pedal work itself loose from the axle once, but I've tightened both pedals down and they've been OK. If they work loose again, I'll apply some Locktite.
The more expensive RXS and RXS Carbon are the same weight as the RXE, so unless you need the float adjustment, you don't gain an advantage with the higher-priced models.
You have to go to the RXS Carbon Ti to get 60 grams less weight. But for around $300./pr. they're not a great value.
The cafe' cleats have been durable, and are easier to walk on than other cleats I've used. I'm still on the original set after over 2 years now, but they are due for replacement soon.