From the creator of 1541 Ultimate we have long time expect to see Ultimate III standalone module that would replace our C64, but author decided to do replacement c64 board for your C64 offering “pretty good” compatibility and software updates to fix compatibility problems.
Pretty good compatibility mean that FPGA implementation of your C64 will probably never reach 100% as there one need a lifetime to test all commodore things and software.
This product is a bare motherboard, which you can place in an existing C64 case or some of newly made C64 cases. The board supports both 6581 as well as 8580 chips with jumpers to select voltage and external filter components. It is too bad that we do not have 2 (4 or more) sid slots on board to have proper stereo sounds, but author offeres also fpga sid implementation.
Another good thing is that there will be a HDMI output with resolution of 720 x 576 at 50 Hz (for the PAL version), also noted as 576p50. From expansion slot you will loose user port but tape,serial and cartridges will still work. I really do not like loosing user port, but I also have a real C64 that have user port and can use 4 joy adapter on it.
And one more important thing to say Ultimate-II+ is already inside of the Ultimate-64 as it is based on the same code. Further more instead of user port there will be also Ethernet port and plan is to release a version with WiFi as more expensive option. Price ? € 199
Source:Ultimate 64