As a White Mage myself, I love having a Scholar in my 8 man groups, we just work so well off of each others abilities and heals. However you won't find that people will prefer one over the other (at least not in my experience), but I could see where some one might take a White Mage over a Scholar if they already have a Scholar in the group, and vice versa with 2 White Mages vs getting another Scholar. Mileage may vary, but don't worry your spot as a healer in groups is secure.