When it works, all is good. Unfortunately it often doesn't work. App doesn't give barcodes, making it difficult to check you are packing correct item. Website regularly cancels my trades, sometimes a couple of hours after items are entered - ziffit is unable to provide explanation. Items regularly 'are not received', although you KNOW you packed every item & in 1 box. Worst of all, ziffit rejects items, quoting generalised reasons, rather than specific to your item and refuses to provide proof of alleged defect. To me this is theft, not rejection. Customer service is usually poor & of course would be far less in demand if ziffit operated professionally & didn't regularly 'reject' without proof / lose items.
Occasionally I get relevant replies to queries/ complaints but usually only after several attempts. The norm is to receive a copy of known ts&cs, or the reply unrelated to my message - if I ask again for a relevant reply, or even make a formal complaint, it is often ignored, despite reminders.
If I traded for myself, I would have given up long ago but I continue as I raise funds for local animal charities and have limited outlets for selling donated items / storage.