>you can enter and exit where you wish in the demo...
Well, not exactly. I used it all day every day for about 3 weeks (I'm talking about the demo in a funded account, not the free online demo software) and often wouldn't get filled. Sure, there were many times I was able to buy at the Bid and sell on the Ask. But many, many times I couldn't.
Usually, however, I was always able to buy at the Ask (or slightly above it) in a running market, or sell at the Bid (or slightly below it) in a falling market. So like I said, it's not at all realistic relative to live trading, but it's not a bad simulator to get to know the software, various order routing, etc. And it's very convenient to use since you don't have to call anyone (during office hrs) to turn it on or off.