At least with urea the rust isnt such a problemBack with Kuhn now, axis 30.1 , no fancy electrics as think lights and indicators can be more than enough sometimes with Fert.
Wasn't planning a change but for what we do the numbers work out quite well to buy a tidy 5 yr old spinner for bugger all, keep it another 5 yrs then sell it for 2/3 of bugger all.