I have an 1818VSL, it is a really solid interface, and it is working just fine for me - Sonar Plat and Studio One V3, all under Win10. That does not mean it will work for you, but at least you know it can work...
I picked up an Apollo Twin USB pretty much as soon as they released it, and that is my main interface now. But I have no complaints about the 1818VSL, and in fact it is still in the rack for those times when I need more inputs (until such time as I can add a converter that supports S/MUX or an Apollo rack!)
My impression (no scientific proof) is that the Apollo sounds different than the VSL, and I might even say better, but it is not a huge difference.
I think the RME sounds every bit as good as the Apollo Twin, and their drivers are the stuff of legend.
I also auditioned the Studio 192 and I thought it probably had a slight edge over the VSL, but it wasn't as dramatic, certainly not enough to justify that upgrade.