I took 4 tours over the two days. The Edinburgh tour and 3 Bridges tour were great. The guides were helpful, interesting and fun.
The Majestic tour was useful because it got me out to the Botanic garden but only because I asked quite specifically where to get off. The Citysightseeing tour was frustrating because there was no indication of what was near the various places being described.
The skip the line ticket to the castle was helpful even though there wasn’t that big a line. Choose the tours for what you want to see.