Is krill the best type of fish oil to take?

No: If omega-3's are the goal - then consider that fish obtain their omega-3's from algae which is stored in their fat cells = fish oil ... But consider all of the potential toxins in fish/krill. Research omega-3's sourced from algae and avoid both toxic fish by products. Why not go to the source? It just makes sense.

EPA Best Evidence: Both epa ; dha, from phytoplankton, at very high (i.e. Purified rx) doses, tend to ↓ the triglyceride concentrations in blood. Epa (without dha ; all the other non-beneficial fats in common fish oil) has a track record of also ↓ing LDL particle number, even at lower doses ; many long-term trials have shown 12-15% ↓deaths thus i commonly recommend purified epa, vascepa, but only 1 gm (capsule)/day.