I keep my router (an Apple Time Capsule 2011) in my living room, but I frequently use my MacBook Pro Retina 15" Mid-2014 in my kitchen, which is separated from the living room by a wall.
In the kitchen, I get roughly 50 % of the download speed that I get in the living room near the router.
I'm thinking of getting an Airport Express to extend my network via Wi-Fi extension. If I were to place it in the kitchen, would it suffer as much receiving penalty as my laptop, or is its capability much stronger, thus warranting the placement to some degree?
Alternatively, I could place the Airport Express in the hallway connecting the living room with the kitchen, effectively "mid-way" between the two rooms.