Of the two, I preferred The Murder Game, set between The Power of the Daleks and The Highlanders. The Tardis crew land on a low-orbit satellite where a small number of people has assembled for a murder mystery weekend; not all the guests are what they seem, and the game shifts brutally from pretend to reality. Lyons captures Troughton's Doctor well (more on this below), and likewise Polly, but the standout character is Ben, who is given a decent past, present and future, and even (albeit briefly) a love interest. I am always impressed when a writer of Who spinoff fiction succeeds in taking one of the minor canon characters and investing them with more substance, and this is a good example.
The Final Sanction is a bit more of a standard romp - Team Tardis get stuck in a space war, Zoe gets captured by one side, Jamie starts fighting for the other side, the Doctor tries to stop the war. But there are a couple of interesting points. First, the Doctor is trapped by his knowledge of the awful end of the war, yet fears punishment from the Time Lords if he interferes. Second, the full perspective of the war is well portrayed - this isn't just two random groups of people in a fight, it's an interplanetary conflict with a real strategic shape. So a cut above the average Who book.
Both books feature Lyons' characterisation of the jittery Second Doctor, thoroughly loyal to his companions but prone to wail in terror at odd moments; I'm coming to the end of my rewatch of the Second Doctor stories, and am impressed by how well Lyons has actually captured him, compared with most of the other books (including particularly the novelisations). The Second Doctor is a hero slightly against his own first instincts. It's very entertaining.