IMO it's easier and more economical simply to clean/lube &/or replace your cable &/or housing on a regular basis. If your routing is top-tube, consider running housing all the way from the top tube to the rear der. (Use zip ties if you don't want to drill out the housing stops.) If the routing is down-tube, it's just that one short length of housing that will need replacing with any frequency.
I have the Avid FlakJacket cabling on one bike, which I'd hoped would hold up under the salty winter conditions in Chicago. Unfortunately though, the ferrules that protect the un-housed lengths of cables are just plastic, and they have sun-baked and cracked after not that much use. I don't know if Gore's housings are better/different plastic/whatever, but I wasn't that impressed.
That said, I'd probably consider buying the FlakJackets again for the quality of the actual housing and cable--besides what I mentioned, they've held up great (and they look pretty cool to boot).