Part of what you found painful about gnucash is probably that it handles cases like this properly. Not saying it (gnucash) is perfect - far from - but a certain amount of effort is I think a side effect of having both proper accounting practice and configurable account types. Not sure you'll find something really easy that also does it well. In your case different peoples expense accounts would keep a rolling tally and help you figure out what the end of month transaction should be to even things out.

But any tech may be overkill. In a e.g. roommate situation, a paper record per month (plus receipts, if lower trust) works fine.