The mags disassemble through pins, which I think is a step backwards. The slide is apparently a new material, which should be good. I read that the mags were improved because of the diecast material, but they said that about the Gen.4 as well. Also it seems to have the same 15mm BBU as the Gen.4, although presumably a different shape.
Don't forget it also depends if you like finger groves on your grip or not.
As a RIF I think it's cool if it's from a film, show or game you really like. I'm not sure what the Gen.5 17 has been featured in yet?
I will also add it depends on what you want to do with it. I've just done a full FDE Gen.4 build with 100% Guarder upper, it's beautiful and works very well. They're working on it as we speak, but it'll be a while before Guarder parts are readily available.