I'm still waiting for the Raspberry people to implement USB booting on the RPi4. It already works on the RPi3B+, just not yet on the 4. Although you can 'hack' the boot options on the SD card and then use some external drive on the USB3.0 port to take it from there on. Running your OS from the USB port should give it a nice speed increase.
I don't have much 4k content to enjoy and just to add a WOL option, which I defenitely will miss, the price adder might be a little to much after all...?
The RPi4 software is still being developed (and we'd all wish things would go faster..), but for standard stuff, the CEC thing, WOL is not a thing (everyone keeps it running at 1-3Watt/hr), overall community support, it's a good deal. Not saying it's the best now.
I'm using my J5005 not just for Kodi, and I basically have no 4K content. So, the choice is still yours