This is another area where there is no 'right' answer - only compromises.
For movies, the requirements on the surrounds isn't that great most of the time and practically anything will do. Per Dolby recommendations they should be placed between 90 and 110 degrees from the listening position and 2 - 3 feet above ear level.
For multi-channel music, the surrounds should be directly to your sides (90 degrees) and at ear level. In this case, having speakers identical to the front three would be ideal although in most homes it just isn't feasible.
Add in the choices of monopole vs bipole vs dipole etc and you have even more possible combinations of speaker type, size, brand, placement etc and no one setup is going to be ideal for all situations.
Sticking with speakers from the same brand or model within a brand is about the best you can do but I don't think it's really necessary for the surrounds to be of the highest quality.