I had a couple of lessons with a stand-in instructor, an AFI, before going solo and felt that I didn't really progress when I flew with the AFI (my instructor was ex-RAF C130s) because they had slight differences in teaching style wrt circuits/landing.
I reckon though that as you have soloed and are into consolidating and preparing for your skills test that it should be less disruptive for you. The old advice applies though - if it's not working for you, tell your new instructor and be clear about what you need from him/her.
Springers