open source s/w have their own forums/support team (the ones i know have!).
many of these contain a feature request thread. why not use their own expertise (of OS accounting s/w u want to /plan to use!) ?
Accounting software is very different from other kinds of software. You can't just pick something up and start using it. And in the case of small businesses, unless you have used Tally for a long time, it is very difficult to appreciate why it outsells all it competitors combined by a factor of 4 or 5. So any replacement has to maintain the 'flow' and 'structure' that it follows even if the UI is different, so that former Tally users can switch over easily. And I don't find any open source software that does that.
Among proprietary alternatives,
Aqura is a good one and comes very close to Tally. We did talk to them and they genuinely tried to solve our problem. But we lost contact with them some years back (the developers moved to the US or something) and the application no longer seems to be maintained.
There are a couple of other alternatives, 'Busy' being one of them. But these applications are too general and don't meet special or specific needs. The only proprietary software developers who offer something (barely) specific are still living in the age of foxpro, dos and making changes to the autoexec.bat file and quote outrageous prices for vaporware. Then there was this famous accounting package for Linux named Kalkulate (god knows what happened to that).
Considering all this, unless someone spends sufficient time looking at the needs of businessmen and making software specific to their needs, writing one's own thing is the only way to go, more so when you know what you exactly need and don't know (or comprehend) exactly what open source alternatives offer.