The Alienware Alpha is far more impressive than it gets credit for. Some people do direct A/B comparisons to the Xbox One and PS4, and get put off by the prIce. ThIs is an unfair comparison, because the Alpha is smaller, more powerful, and a fully functional Windows 8.1 PC.
I've upgraded my Alpha with 16GBs of Corsair vengeance Ram and a Samsung Evo SSD, and it runs wonderfully. I have the i7 model, so it came with a slow Samsung 5400 rpm 2TB drive. I've since put that drive in a USB 3.0 enclosure and converted it into an external drive, and do you know what? It runs faster as an external drive.
In addition to this, I've run the system at 4K, and it works great for everything except gaming, of course. However, I do use MSI Afterburner to overclock the GPU +135 Mhz and the memory +550 Mhz and have gotten some great results. It handles everything I've thrOwn at it with better than "next gen" graphics and framerates. It's a great, tiny PC.