To me its more than a so so card in terms of AMD, its a fast card without being brut force, to be honest i think Nvidia are the yard stick for that, you have to compare AMD's cards to Nvidia because for a long time now they have made cards that are much more efficient than AMD's cards.
With that a 5700XT has 2560 Shaders, 256Bit 14BG/s GDDR6 and it runs at about 1900Mhz, identical specs to the 2070 Super and the performance is the same.
Now look at AMD's previous generation, The Radeon VII, 3,840 Shaders, 1900Mhz, HBM2, on the same 7nm its 40% larger. Its no faster, in fact some reviewers are saying the 5700XT is starting to overtake it.
Per shader per clock RDNA1 is more than 50% faster, its every bit as good as Nvidia's Turning, it is AMD's Ryzen 1000 GPU.
If its a "So so card" then so is the 2070 Super, and i don't think it is. the 2070 Super is also £100 more expensive.