If I bought my wife something exercise related for her birthday it would be the last one I saw
I have used the Fitbit and I really liked it, it was just the flex and really only recorded steps and sleep patterns (my favorite feature) It syncs up nicely with PC or smart phone. There are the 3 higher models the The Charge (has time on it) and Charge HR which has a built in heart rate monitor and most of the reviews I read about that version is that it wasn't very accurate.
Here is the comparison chart but I found that just having that constant reminder on my wrist helped keep me thinking about fitness
https://www.fitbit.com/ca/compare