Try to check out both red and burgundy at the same time to compare, and if you after straight/true red then go for red if you after dark red, then go for burgundy, at least I can say this burgundy not change colour dramatically like 18b dark pink that change to pink in bright sunlight (but Look very nice in the shade).
Good luck!!
These are for referencesLooks so pretty in this picture...do you see any brown undertones when in sunlight?