I think there are many advantages to not using Excel, as beyond a certain point it becomes needlessly complicated. That said if at the moment you are just using Yes/No's then there is still a lot more you could do.
If you have someone in your team who is really good with functions and macros you can do some really interesting stuff. We use an excel form, and it can be used to score an agent, look back at their past results (as either charts, numbers or a form) can be emailed to the agent. Ours allows for actions to be logged, which can feed in to managers into a list of actions and deadlines.
Sometimes Excel gets a bit of stick, but in the right hands it can be a quick cheap option with no real compromise over a purchased, and the advantage that it is much easier to change compared to a dedicated piece of software.
I once whipped up in a day a customer database management workbook which prioritised customers for outbound calls. Some of the guys over at the professional planning forum suggested software with the same functionality would cost at least 10k, and I have seen little evidence to contradict that, so I am usually of the opinion that the main limit is ones imagination.
Unless the number of interactions you are grading is pushing a hundred a day, I wouldn't rule out Excel.