Don't worry, the nicer stuff won't always shift nicer either. I tested out all Altus......all Acera......all Alivio......and All Deore. You wanna know what differences I noticed?? NONE, except for the number of gears! In fact.....dare I say I'm so used to (and pleased with) my Altus shifters & Alivio RD, that anything else would probably feel weird.

Getting your stuff setup right will make a bigger difference than make/model.

In fact, if you want real proof, you already answered your own question in your OP!!