Configuration is not free
Every unit conversion you define, every custom field you add for a vehicle number, every workaround for site-wise delivery is time now and a thing to explain to your staff later. A general product can usually be made to do most of what a material shop needs. The question is what that costs in setup and in the daily friction that follows, against a product where those things are simply the default.
The four things worth testing
Whether the unit and its conversion live on the item, so nobody does arithmetic at the counter. Whether GST sits on the item rather than the bill, so a mixed-slab invoice comes out right. Whether the delivery record carries a vehicle number, a site and a receiver. And whether credit shows ageing rather than a balance. Test those four on your own bills and the decision usually makes itself.
Where you should stay put
If your shop is general — you sell items by the piece at one GST rate, mostly for cash, with little credit and no deliveries — a general billing app fits you better and moving would gain you nothing. Most shops in India are like that. The switch is worth it specifically when your trade has habits the general product has to be bent around.
Moving off a general billing app
Data comes across easily; the configuration you built up does not need to. Export items, parties and outstanding balances and leave behind any custom fields or workarounds you created to make the old product fit — vehicle numbers squeezed into a notes field, units approximated as pieces, delivery details written into the invoice remarks. All of those have proper homes here, and carrying the workaround across would recreate the problem. Expect to spend the setup call mostly on units and rates, because that is where a general product left the most to be desired. Thirty minutes, a real bill at the end of it, and the item list keeps growing for a few weeks as you sell things you have not entered yet.
Setting up units properly is the whole job
If one part of this migration deserves care, it is this. For every item you sell, decide the unit you sell in and, where it differs, the unit you buy in and the conversion between them. Steel bought in tons, sold in kilos. Tiles bought in boxes, quoted by the square foot. Wire bought on a coil, sold by the metre. Cement, straightforwardly, in bags. Getting these right during setup is what removes the calculator from your counter permanently and makes the stock figure mean something. Getting them approximately right is worse than useless, because the arithmetic looks automatic and is quietly wrong. Our team goes through them with you rather than leaving it as homework.