Yes do make sure to get brands that have heavy metal testing as MANY brands have high amounts of lead, arsenic, mercury, and cadmium way above the RDV.
a lot of people even those without allergies have digestive issues with some forms of whey protein, different blends can be a bit easier on the stomach.
You also do not want to bother with soy protein as that is just junk.. Whey or Casein is the best version and helpful for the body.. It is just difficult cause many people are allergic to these types lol.
I would go for casein if I were you, judging you are not allergic to it.
here is a good brand name for it and heavy metal free!
http://www.hammernutrition.com/
Just look at the casien versions of protein powder, rice is okay too but not as beneficial.
Also just in case you are on methylation protocol of any kind then whey protein is a big No, No. lol Though I don't think you mentioned doing methylation.