A little bit Google and checking in shops can help a lot!
First, all Digi dry cabinets sold here in SG come with 5 years local warranty (bring-in service). There are threads here in forum describing that service is quite good. You can either bring in the dry unit only (if you know how to disassemble) or you bring in the whole box. Not an issue for 30l and 60l boxes as they not heavy. There are not many cases reported about faulty boxes.
Secondly: if you don't like 2nd hand why do you even consider this? Used stuff is used, not new. If you need the insurance to have new gear then you have to pay the higher price for new box. But even this will not prevent that your box might stop working one day. For this you have the 5 years warranty.