It's a small coach that fits maybe 15 people, and a very knowledeable, friendly, tour guide that takes you wherever you signed up to go. You stop a couple times, so you're not riding in a bus for the most part (unless you go all the way up to Loch Ness), and you get a few hours to explore at each stop. This is a full day tour, but at a great price. And if you're a student you get a discount. =)
The best part is seeing a variety of Scotland, and hearing all about the history and interesting stuff along the way.
The trips we took were The Trossachs, Loch Lomand, and Stirling castle (one tour); St. Andrew's, and Fife; and the Highlands tour up to Inverness.