Bought my Ultegra Di2 Synapse last summer to replace my beloved ‘92 Merckx Century. I have ridden Campy bikes since ‘75 and had been a loyal Campy customer, but finding a built Campg bike is difficult abd expensive. When looking at bikes the cost of components on a built bike made them far more attractive. I settled on the Synapse after trying a Bianchi Infinito and. Trek Domane. The cost of Di2 still made the bike a great deal compared to building up a bike. I have no regrets at all about Di2. I love it. It works flawlessly. If you have a Wahoo head unit you will know far in advance if your battery is dying. It is almost literally impossible to have it die on you given the amount of battery life left after the warning. Failure to heed warning is a user problem. The other thing I love about using it with the Bolt is the visual gear indicator. As with many bikes the wheelsets that come with them are usually not great, but are one of the easier items to upgrade.
I would have no hesitation at all buying the Di2 Synapse.