If you want to complain something about the product, I think unfinished software would deserve more attention. The current desktop performance doesn't reflect the capabilities of the system. I guess it'll significantly improve once OpenGL ES 3.2 (and hopefully Vulkan!) drivers will be complete.
Other minor issue I had was RPi4B not recognizing the HDMI display. I had to manually force it and this caused loss of HDMI audio. Using the official Raspberry Pi branded micro-HDMI cable.
I hope Raspbian will eventually have a 64-bit version. Out-of-order cores can benefit from more registers in 64-bit mode. More registers allows the compiler to reduce true and false dependencies, leading to faster code execution.
CPU wise it's nice, quad Cortex A72 is a huge boost compared to A53. Hardware accelerated omxplayer can play 4K HEVC content nicely. USB 3 ports have up to 4 Gbit/s bandwidth, and it's not shared with the now truly full speed gigabit ethernet.
I'm very happy with the product. RPi4B is a very capable system for its price. And it'll just get better over time.