[bastijn]

I think there is a difference between in-house developed platforms and platforms bought externally. Apart from that, if that 80% is of high quality and suits your needs doing the last 20% yourself is of course the idea. A platform can't give you 100% as it isn't tailored to your specific needs as a product. It shouldn't be in the way for the last 20% that's what a great platform should be. Kick-start you for 80% and not be in the way for the last 20%.