No, I would say a PCIe SSD has no place in a gaming PC. Those are designed for those who write extensively on the drive and are best suited for proffesional application. An SSD (no matter which kind) does not improve your framerates over a HDD but makes load times faster. I'm guessing you would't see a noticeable difference between a SATA III ssd and a PCIe one unless benchmarking or sustained writes (none of them used in a game). Indeed some games benefit from being installed on an ssd (e.g. BF4, or games with frequent loading) (it will reduce load times), but a PCIe SSD is overkill for this purpose (also they are very expensive).