As for slow, I can tell you that is a function of the connection type. our POS Dealer has a contract with Huges Net (sattelite) for our current system. takes about 8 seconds to negotiate due to ping limitations. if they scan a rewards card, add 15 seconds between hitting subtotal and again after hitting the payment method.
the new POS system, they wanted to originally have it cellular based, but considering the quality of service around here, no thanks. My boss pushed and found out broadband was a option (the on site tech had no idea) but we need a dedicated line just for that (no sharing the current Internet) with a cellular as backup.
Still no ETA on when they will swap the hardware for either company
Oh and the companies are Cardtronics (ATM) and Verifone(POS)