entry level bike giant ATX 27.5 2 or Specialized Hardrock V 650b

I'd like to buy my first mountain bike and my budget has led me to these two options. Which would you choose and do they both have the same potential for upgrades? Thanks

https://www.giant-bicycles.com/en-us/bikes/model/atx.27.5.2/22194/84074/#specifications

http://thebikeshoptemecula.com/product/specialized-hardrock-v-650b-236758-1.htm