Jury is out here yet . I have my old 024 with screw on caps that the fuel has leaked some since it was new and you have a very hard time to get the oil cap off because it seats so tight , that design sucked . My 026 those screw on caps work great did when they were new and still do . The screw on caps on the 180's work great too just hand tighting , infact I like those big caps and also like the chain adjuster on those saws as they are used for brushing saws and if you pop the chain off in the bush you can put it back on with out any tools but those saws and there purpose is the only reason i like the tooless chain adjuster . Now the flippy caps I have a 192t,260 ,360,361,460, What sucks is all the crud that gets into spots you cant seem to get it out of along with all the crud in the tank grooves I spend more time trying to clean out the caps then use the scrench to open a screw on cap . Whats nice they are quick and tooless . All of mine work good with no issues except the oil cap on the 360 , I am on my 3rd one . It never seems to line up right or seat right , There for its been 2 broken already , but they never leak on me , infact I have no flippy caps that leak .
Best thing I have found for cleaning flippy caps before fueling is we use cans of compressed air for blowing out the dirt . Or an air tank works good too .