Not sure of the market you are targeting. It has been my past experience developing and selling stock/sales system in India that it's very hard to break in with a browser based remote model (vs. FoxPro, curses) based interaction model. The main reason being adoption. Some of these adoption issues are.

- Hot keys

- Popups (like FoxPro) and selections.

- Local vs remote (availability) vs sync later. Syncing has to be automatic with extremely good fail over mechanism.

- Install once and forget about it. What I mean here is that retailers (at POS) are not thirsty for new features/functions.

- Forgiving.

My2Cents worth.