Try logging everything to make sure your gets and token generations are working:

Log::debug($user);
Log::info($verificationToken);
// etc...

Also, try running composer update if you're on dev-master. There was a commit last night that seemed to break just about everything that has a ->where() in it, but it's fixed now.

I'd suggest you to install laravel-debugbar, and check all the queries.

Exact same issue here solved by allowing the my "access" field to be mass assignable and using the update() instead of save().

public function activate($key) {
    if ($this->confirmationCode()->getResults()->key == $key) {
        return $this->update(array('access' => $this->access['verified']));
    }
    return false;
}