I think I will stick with bel-ray air filter oil.
No toil works pretty good but if you put in clean filter and dont ride all week for some horrible reason , the no toil will try out and then you are left with a filter with no sticky.
Besides a savy rider gets in the habit of cleaning the filter after every ride and also should change the oil after every ride.
When I talked to Scott at NoToil, he told me they had a filter sitting around to see if it would dry out and if I recall, it's been well over a year and it is still tacky.
I think the drying out that some are refering to is with the rim grease. They did have a problem with it but it has been reformulated and stays soft now.
The rim grease is what dried out on me. I'm not sure how to tell the difference between the old stuff and the new. The tube that dried out was purchased at the end of the summer, out of a fresh shipment from a distributor.
dix - I think the older rim greases were red (and blue). The one that I currently use from No-Toil is dark green. So you should be able to tell by the color.