I bought my mare recently from a lady that was getting out of horses at my barn. She is quite young, 4, and off-the-track. She's a little flighty on the ground but nothing I wouldn't expect from a 4 year old.
I have noticed under saddle she's responsive but almost sluggish. To keep her trotting or at the canter for longer than two strides I have to keep my leg on her. I'm contemplating spurs. I use them normally but haven't with her because I assumed (ha) that she would be super freaky under saddle.