I have heart disease and arthritis and both are supposed to be helped by the intake of omega 3 fatty acids. I have tired both and have decide I like the flax seed better.
I do both, but I take fish oil capsules and use flax seed in baking bread. The flax seed I store in the freezer because it goes rancid quite quickly... I put a couple big spoonfuls in the dry ingredients and it adds a nice texture.
I take mine in a capsule the company I have an online business with sells them and they are organic so I just buy mine form them. I don't like the smell of the ones that come from fish oil.