Modern electronics means most hi-fi is pretty decent, the bit that stands out is the speakers. That's the area a lot of low end companies skip on in their systems. Quite often seemingly poor stuff can be massively improved just by swapping speakers.
strange to find myself agreeing with serious
Hi Fi is an area full of absolute bollocks - if you go on some Hi Fi forums you'll find a whole bunch of complete morons spending silly money on magical speaker cables* or convincing themselves that some CD player is somehow giving them better 1s and 0s than some other CD player or maybe that spending more money on a £50 HDMI cable is going to have some magical effect on a digital signal! (which makes about as much sense as spending more money on a gold plated RJ45 network cable to get 'better internet')
The reality is that modern amplifiers have minimal distortion and people generally can't tell the difference between them in controlled, blind tests. Ditto to CD players - modern DACs are pretty much a solved problem and can be mass produced cheaply - if you're going to send a digital signal to your amp anyway and use its DAC then a CD player is a CD player... they're all literally just sending the same bunch of 1s and 0s.
The factors that make a difference are the layout of the room, position of the speakers, what sort of surfaces you have (wooden floor vs carpets etc..) and there are noticeable differences between speakers.
So long as your amp is powerful enough to drive your speakers then you're sorted and really you should just pick the amp based on it having the features you require.
*they ignore the fact the inside of the amplifier contains ordinary printed circuit board and ordinary connectors and ignore the fact that inside the speaker is several meters of ordinary coiled copper cable the few ft of super special magic speaker cable connecting the amp to the speaker somehow enhances the sound in ways that make a wine snob sound unpretentious