That's actually a really good question...I'm going to follow this discussion as I'm interested in other responses.
Because I didn't have a ton of cash when I opened, and only room for one register, I just have a regular Casio. If you have the $5,000 to do the big fancy computer register, I'd imagine that's the way to go since employees can sign in and out of it, etc.
Currently, I only have two employees in the shop at a time and sometimes the back person has to jump on the register to help out the counter person so, unfortunately, we don't have a really controlled process...4-5 people a day handle the register and then the evening supervisor does a balance sheet. I have really good, and I think honest, kids, and we usually end up within a dollar +/- every day, so switching out tills at the end of shifts hasn't really been necessary...yet! I don't have very high sales yet, either, so I'd imagine I'll have to switch the process once sales go up.