[dmak]

It is definitely a saturated space. However, only a few competitors are agnostic to platforms (Splurgy, RaffleCopter, gleam.io, and a few others). Other competitors such as OfferPop, Woobox, Shortstack, and etc... are all Facebook centric which means you cannot embed your contests/giveaways on your website; This means you won't be able to funnel your existing website traffic into your social properties.

Also, MailChimp is not over engineering at all. It's a very key feature. These integrations are important for marketing teams. After people socially engage into these contests/giveaways, their emails are captured and then can be ported into MailChimp where you can run e-mail campaigns.