There is no simple perfect answer to your question. We don't know the SEER rating on your equipment either. A minisplit can go for many years with little maintenance and they have millions of Fujitsu's in Asia, Russia and Europe. They are very reliable but like a Porsche are very specialized and expensive and need a specialized tech to repair. This may limit the competition or choice of companies who can repair them and they can charge whatever they want. The heat pump combo is a lot easier to get repairs and shop around for repairs. Electric strip heat is 99% reliable and very simple. I would lean towards the heat pump combo, but I am a believer in minisplits also, mostly for jobs where there are no other options.