They would both be technically compatible with any board that supports DDR2 (DDR2-800 support for best performance level of course, which every board that supports Conroe has). It's debatable which one would perform better, since some of the latencies are lower in one, but other latencies are higher. It's kind of telling that the one that looks like it ought to be the "super special amazing" stuff because it's got heatspreaders on it is actually a lot cheaper.
Even though they would be technically compatible, many boards have stability issues or even fail to boot with particular modules, which ought to work based on the specifications. You need to find out which mainboard you plan to use, in order to determine the best memory modules to use.