It's a far cooler form than anything super saiyan related in the series, honestly.
Much better concept than Super Saiyan just randomly spawning other transformations like Ssj2 and 3.
As far as general aesthetics go, it's my favourite SSJ form by a large margin. As for it's concept, however, I probably prefer Super Saiyan God for the reason Fearless mentioned. Attaining SSG was a lot more different as far as SSJ transformations go.
While I'm not that much of a fan of the black and pink color-combo (I would have honestly preferred if it was simply all gold),
I can appreciate the fact that it's not just a bit of hair dye and an aura change.
I like SSJ 4. I also like SSJ Blue and SSJ Rose(most the SSJ Rose Aura) is cool. I dont really care for the weak lean look of the Saiyans. It makes them look like a soccer player instead of a badass warrior who destroys world. I guess its become common with current trends in Japanese Manga. I just think SSJ Blue that looked similar to Goku on Namek would be awesome.