Stagecoach is a bit of a lottery ime, it's a franchise so some are ok but lots aren't. Also ime they are unable to really "get good" as they just don't do enough.
My advice would definitely look at a school with a good reputation and start your dd doing ballet (as this is the foundation for all dance) and then add in modern, tap, jazz Etc as the teacher advises it.
I know several children who have done stagecoach, but the ones that are any good do it on top of more specialised classes. It's run for the masses, in a one size fits all type philosophy and ime that's just not conducive to every child.
My 4yo dd (she is almost 5) currently does ballet, modern, street jazz, Greek, and song and performance. That's a lot for a child of her age but she comes from a family of dancers and has lived at the dance studio since she was tiny. Most children her age (at our studio) do ballet and maybe modern. She is begging to start tap but I am holding her off until September!
It does get expensive quite quickly, but I have four children all dancing a lot and I think it's worth it. Mine dance competitively and I would much rather they were at the studios than sat in front of the telly, or hanging around street corners.
Look for accredited schools, perhaps look at the RAD or ISTD websites for a teacher in your area (or IDTA/ BTDA or BBO). These are all examining boards. Also try and find a school that covers most genres that you think your dd will want to learn. It's best to stick to one school ime. Some teachers don't like you going elsewhere and if you do go to one school for one thing and another for something else then you will eventually come up against timetable issues!
Also think about If you want your dd to dance competitively or have the chance to perform regularly. Some schools don't go in for competitions (usually known as festivals) so that's something to be aware of.