Different parts of the funnel
Wunderkind is about recovering more reachable shoppers. Klaviyo is about marketing to the profiles and customers you already manage.
That distinction matters. If the problem is anonymous traffic, Wunderkind is closer. If the problem is lifecycle marketing, Klaviyo is closer.
Where Wunderkind wins
Wunderkind wins when identity and intent are the missing layer.
Where Klaviyo wins
Klaviyo wins when the team needs a powerful ecommerce marketing platform for everyday email and SMS work.
Where Sequenzy fits
Sequenzy fits when the work is email automation, not identity resolution or SMS.