From what I can gather in the testing of the Cuirassiers in my test bed set-up, these are definitely a benefit to the DDR1 world. With voltages being pushed well past 3.0V on some of my own DDR1, I would have loved a set of these to try to get every last MHz out of my RAM. With DDR2 at extreme overclocking levels, the Cuirassiers still have a place to do some work, show some benefits and look really good. With DDR3, my thoughts are this; If you aren't going to very extreme levels, I can't really see much benefit other that appeal of the design to add to a system that needs that little bit extra. The voltage for DDR3, being so low, it just doesn't seem to fall in the sweet spot of the Cuirassiers cooling zone.
As I have mentioned, Xigmatek also makes the Dragoons as well. These are a H.D.T. model of the Cuirassiers I tested today. I would really like to see if a copper pipe running across the IC's to an external arrangement of fins, has a better margin to cooling. I'm not saying the Cuirassiers don't do what they are intended to do; they do actually show cooling benefits, even if small, and do look really good once on the motherboard.
For the average Joe looking to spice up his rig and cover some value RAM with a clean and flashy "plating", these may be the heat spreaders for you. For the extremists in a few of us, with DDR1 or DDR2, the Cuirassiers do prove they have a purpose other than good looks. Personally, I really liked the overall look, design and ease of installation. With an asking price of around $16.99 plus shipping, I can't say that they aren't worth the price based on looks alone, as almost all of us have spent more to spruce up our rigs with parts that aren't even regularly seen.