Hi, the current release of Bluestacks for OSXworks though you need to be running 10.9 Mavericks or better. I'm using Mavericks loaded on a Class 10 32GB SD card which I boot from. The MBP is a quad core I7 with 16GB of ram. MW is actually a lot faster then on the iPhones and iPads but with the speed comes a problem with accidental clicks especially after you get used to the glacial pace that the game plays it on IOS. I have not tried free gold actually but it should work since all the menues etc are Android not IOS. Scrolling can be a PITA though but if that's all you got...
I also set up Bluestacks on an HP core I7 Elitebook with 16GB of ram and 512GB SSD running Windows 10. Again blazing fast same other side effects though but again a good doomsday setup.
But I set these up mainly as a backup to my IOS and Android linked accounts since the real hardware has been prone in the past to lockouts. Potential downside is Bluestacks support can be flakey, for a while they discontinued OSX support and it's a question if at some point it goes away again. Also in the past gree appeared to lock out those on Bluestacks with a couple of upgrades.
On the PC side it can be really hit and miss with your video drivers. Dell's are a mixed bag of hell, HP seems slightly better. My gut feeling is that the more mainstream the card the better. CPU was, I've gone as low as a P4 but honestly it's so slooooow that it isn't worth it. Bare mimimum would be a Core 2 Duo though i5 would be a lot better. A SSD also makes a world of difference.
Hope that helped.