"Mackenzie's Magic" is almost a keeper. It has a very nice twist on time travel, and the heroine is spunky and smart, and doesn't want to change. Mackenzie, while definitely rough around the edges, is a likable fellow and definite marriage material.
However, the reason I could not give it five stars is that the main characters kept having the same argument throughout most of the story. Mackenzie thought he accidentally traveled through time because Jane Everleigh was a witch; Jane thought Mackenzie was mentally ill and hadn't traveled through time at all. So you would get this in varying forms:
"Send me back, witch!"
"I'm not a witch! It's the illness!"
I thought that if I heard "It's the illness" one more time, I would scream. I do realize Jane was mechanically repeating the same line every time the subject of time travel came up so she would not have to deal with the reality of it. It is a valid reaction to something so off the wall happening -- but nonetheless terribly, terribly annoying after you've read it about 25 times before.
Truly, overall the book is really great. It is a nice time travel, with more realism than expected, a strong heroine and a hero you don't want to sock in the eye. If you can handle the constant "witch, illness" arguments, it is definitely worth reading.