If gaming and photoshop are the priorities I'd stick with intel. Ryzen does have a significant advantage when streaming or video editing/encoding. This doesn't seem to be one of those situations. I certainly wouldn't sell mobo, ram and cpu for $300, they're offering $180 for the cpu alone. So they figure a a z series mobo and 16gb ddr4 ram are worth $120? That's nearly the cost of 16gb ddr4 alone if one had to replace/buy it (at least in the U.S.). The $180 offer for the cpu isn't too terrible, if looking to upgrade I would go with the 7700k.
If you do heavy multitasking, actual multitasking like a video encoding in the background while a 3d image is rendering and playing a game all at the same time, ryzen would be a better choice. Some mistake having a lot of tabs open as multitasking, it's a lot of single tasking and instead relies on ram to keep so many open things readily available in memory. A lot of things have potential but unless you need them or plan to use them, potential doesn't make things go faster. Having a lot of threads/cores is kind of like having a dumptruck. A useful tool if you have metric tons of dirt to move. If you just have a few bags of groceries the advantage isn't there.