Which washer is better Amana or Roper?

They are both made by Whirlpool, and their basic models are probably identical except for minor cosmetic differences. If you like the looks of one over the other or can get a better price, go for it!

On the other hand, if you want to move up from the basic top-loader, and add a little capacity and a fabric softener dispenser, or even switch to a front loader, you would have to go with Amana, as it has three models, while Roper only has the one. (at least in 2023)