The Zotac is terrible value. It's 5.8L and uses a proprietary motherboard and an MXM GPU. With the 3.5L Mini you're getting a much cheaper, more powerful system that uses off-the-shelf components and is 40% smaller. If you don't want to wait, get any of the other 4-7L cases in production advertised here or on [H]ardforum SFF. Or consider the ASRock Deskmini GTX, which uses MXM too and is not good value, but at least it's really tiny at 2.7L or even smaller if you put it in a custom case.
I thought the En1060K is sub 3L too with the specs?
https://www.newegg.com/Product/Product.aspx?Item=N82E16856173145
If i were to buy a 3.5-4L case, I would like to use my old parts and just buy a new EVGA 1050TI. As stated earlier i have a 2500k which till is enough today, imo, and I only play LoL and want to use my 144hz monitor.
Ofcourse as silent as possible is important and from my understanding cooler mounting could be troublesome for the asrock.
I Live in sweden and its a bit hard to get a hold of asrock mini and easier to get EN1060K.