*just a side note to say 'best' in this context means 'most re watchable' to me
Best episode - Homecoming (special mention to Transference, Onyx, Splinter, Blank, Insurgence, Shattered, Hex, Red, Rage, Justice, Exile and Phoenix, Memoria, Nemisis, Combat, Identity
and of course Pilot!)
Best season - Season 3 (though I did love 1, 10, 9, 4, 6 and 2 as well as parts of 5 and 8. So basically everything but 7. Siren is the only episode I liked in that season)