Well not the strongest, it seems since Release day people have been figuring out how to make Hunt Alone Hunters work out, mostly thanks to many the KaC cards like Flanking Strike and Wandering Monster and the Spell Stone. Kibler was actually able to get 100% win rate for a time with this till he hit a Warlock control wall. Again its not the kind of archetype people wanted for hunter but people are making it work and work better then people expected.
It turns out Spell Hunter decks even though far from being meta breakers are very competitive, a borderline tier 2 archetype. It only feels truly bad to play against Cube and Control Lock, everything else is manageable as long as you keep the right mulls and do the right calls.
Like I mentioned in this very thread, it seems like Barnes/Y'Saaj package fits like a glove into Spell Hunter as well. Currently at 400~ legend rank and 6-0 with it.