I'm impressed with Kodi which would fulfil most of your requirements. Picture and audio quality are excellent.

It supports BR ISOs but not full menus (unless you add an externalplayer such as PDVD) and is best suited to MKVs. There's an excellent add-on for Amazon instant Video and several for live TV. Recording TV is still a bit clunky and not a route I've gone down. I believe there is a Now TV add-on but I've not tried it.

Setting up does require quite a bit of work and it depends what kind of solution you want.

Main system - Sources (Kodi-HTPC, Vero 4k, FireTV, Sat) into Trinnov Altitude 32 (8-16) (+Roon), Trinnov Amplitude 8 amp & Vivid Audio (Giya G3, V1.5) and REL Stentor III speakers. Others: F80 + Raspberry Pi and other Pi systems.