well, the less outside interference, a.k.a. dust, moisture, bacteria, viruses, and anything else, the better. if buying something fancy can do the trick, then...hell..why not? if it will preserve the system just that much longer, and means you'll have to spend less in the long run, it's a worthwhile investment in my eyes.
as for switching back to air, i'd say...if you can go with something without air then do. because air is so tricky to deal with. all the fans have to be placed exactly right, otherwise there will be a pocket where heat will gather and potentially ruin part of the system. fans also have a tendency to occasionally be ineffective. they also tend to drag dust INTO the system, and that clogs up the heatsink and other heat transfer measures and renders them almost useless.
if you can avoid problems like those, then do at all costs. i'm sort of delivered because what i'm doing has to be done with my pocketbook in mind.
