I think Spree will eventually use MrDelivery seeing that Takealot and Naspers are cosy now. I don't think Spree holds much of a future. It will either be shut down or absorbed into Takealot. I doubt a merger/takeover will happen, as Superbalist has been doing fashion for quite some time and it would only make sense to shut down Spree as part of Nasper's consolidation strategy (BTW: The next big thing will be food services - watch this space)
Without going into much detail, the Efinity bidorbuy experience was far from ideal and technically superb as I hoped. We started integration middle of July 2015 and ran into unexpected issues with their APIs and sandbox environment. A typical 3rd party integration would take us no more than 6 weeks and it took almost 4 months (completed in October 2015) to properly integrate (most of it was due to their focus spent on Spree - so we never really had priority). The way "changing focus" happened and how it was communicated, was highly unprofessional in my books and not the way one conducts business and I doubt that Media24 will ever be successful in e-commerce with such leadership and conduct.
Most sellers do not like to drop-ship / stock their inventory with a 3rd party and typically costs become excessive (especially when some players offering a similar service to Efinity start charging for re-stocking fees for returns or non-delivery-attempt fees etc). Having said that and without derailing this thread too much, another player will launch a quite disruptive fulfilment solution during Q1 (around Feb 2016) which will work substantially better (and cost-effective) for the adhoc sellers and small businesses.
In fairness: Most fulfilment companies have some shocking IT infrastructure and development skills. APIs and endpoints are poor without proper security (most fail the basic Qualys test and are still vulnerable to Poodle/Beast and have weak ciphers. Hardly anyone has IP-to-IP security and most API's fail the most basic OWASP-top-10 security rules - none of them would pass a POPI compliance for example).
Something to watch: Keep a close eye on Mark Barnes (SAPO CEO) - it is only logical that he needs to reposition SAPO to be more e-commerce friendly (Deutsche Post AG did the same when they unbundled from the state, bought DHL in early 2000 and are now the largest freight company in the world) - no other company in SA has such a wide-spread footprint as SAPO (yes, I am eternally optimistic and do think that with the right focus this can happen)