It might be hard to say exactly which company makes the best memory foam pillows for side sleepers because there are so many of them out there. Memory foam is one of, if not the most popular type of pillow on the market today.
The best place to start when you need to choose a side sleeper pillow is to figure out whether you will be better served by a shredded memory foam or a solid memory foam. Many like the shredded foam because it is more flexible for them than the solid foam. Others like the solid because it gives that uniform shape throughout the night.
The thing about being a side sleeper is that our heads are further from the bed at night than those that sleep on their backs or even on their stomachs. We need a pillow that can fill that space between the head, neck and shoulders when we are at rest. It the pillow does not hold its shape well during the night, then we will constantly be waking up to fluff and position it.
I visited places like http://luxuryofthepharaohs.com/side-sleeper-memory-foam-pillows/ and was able to view many different memory foam pillows that are suggest for side sleepers. It wasn't easy to make up my mind, so I bought a couple of different ones and tried them out. I ended up using the solid memory foam pillow by UTTU more because of the removable foam, but the one I purchased by Eden is very nice as well.