Like people, shaving brushes come in varying shapes, sizes and characteristics. And we shavers have preferences for creams, soaps, or love both and have different preferences for making and applying lather. So brush makers try to meet these different needs. Some brushes are soft and floppy. People with sensitive skin may prefer them. They also work well with creams. If you like soaps, you may prefer a denser, stiffer brush to generate lather. Some people like to make lather in a bowl - any brush will do that. Others prefer an exfoliating scrub while building lather directly on their face. A firm brush is better for that. And then size. You can get very small or very large brushes. Most of us stick within a knot size range of 22mm to 24mm. (This is the size of the base of the knot)
All brushes can be used with soaps and creams but some are better at each job. So it's generally soft for creams and stiff for soaps. Something in between is a good all rounder.
Once you start using brushes, you will inevitably end up trying more than one. Only you will decide what's best for you. Once you decide the characteristics you want in a brush, any number or reviews will help you to identify a brush which may suit you. It may cost a bit to find out!
The photo shows a rather floppy Edwin Jagger Silvertip and the Simpson Duke 3 Best badger - a firm dense all rounder.
These threads are worth a look if you really want to get into detail:
A guide to choosing a brush
Picking and buying advice