If you like the design and operating system of a Macbook Pro, I'd go for it!
However, the price is exorbitant and you can get a better GPU option at a cheaper price. The new integrated Intel GPU are enough to handle LoL at low to medium settings. So if you're okay with that, I'd go for it (I used to have a Macbook Pro and played LoL on it).
I love the battery life on Macbook Pro's and the overall ease of use in the OS.
I'd also recommend this (http://www.amazon.com/ASUS-N550JK-DS71T-15-6-Inch-Touchscreen-Laptop/dp/B00IAA5BSS/ref=psdc1_t2_B00K2O4S0W_B00IAA5BSS). This can run LoL on high settings and it's a cheaper alternative to the Macbok Pro.
It really depends on your preference towards design, OS, and cost.