Pretty sure this is more a matter of preference anything else. It depends on what you want to do with the two of them. I don't think you have to have the same brand on each device in order for them to be compatible. You just may have a few more things you can do between the two Samsung products with the Samsung Account if you decide to get that.
At one point I had a Samsung phone and a Nexus tablet. I didn't experience any problems with the two different brands.
As long as they're both Android devices I personally don't know of any major problems we might with two different brands.
Notes from Deb's Note 3