Receipts mean nothing but a feel good. All the receipts in the world won't mean anything. How they are counted means everything. You don't see that in any computerized system. You lose the audit trail and chain of custody.
Paper ballots. hand counted by at least two people with witnesses and a very, very hard chain of custody of the ballots and the results. Make sure, even with hand counting, what's posted on site matches the hand counted results.