Yes I have also read a ton of good reviews about that one. If it's not out of your budgen then get it. You cant really go wrong with these coolers. They will do what they are made for.
If one performa an inch better than the other who cares.
Didn't your X2 come with the AMD heatpipe cooler?? Which is more than adequate for 2-6-2.8 Ghz (which is all you will get out of that chip).
The aftermarket coolers are only slightly better than it, maybe a bit quieter.
I don't think the 3800s come with the stock heatpipe cooler. My AM2 didn't. My rig was getting too hot for my comfort (55+C) with a 400Mhz oc. I got the Zalman 9500 and couldn't be happier with it! My load temps with the oc are <45C now.
Personally I've put a AC Silencer 64 and AC Silvr 5 on my X2 3800+; it's a s939 one. I pushed it to 2.4 GHz as an afterthought, no voltage modding. Even C'n'Q kept working fine.
I dig Arctic Cooling HS+fans: cheap, efficient, silent. I have several.