if your POS is point of sale and not piece of sh6t.
i use Sage/Pastel .25 yrs now .never had a real issue yet if its in the cloud Sage does everything for you .easypeasy .if you keep stock and have a large inventory its brilliant .
ive never tried anything else .make sure you can easily add stock with cost price .retail and discounted price it makes life easy .vat and tax must be sars compliant and easy to do .
Loyverse App does that quite well and its free!(interms of the sotfware)...so its a merge between android/ios based hardware and App based solutions...