You want to buy a mobile phone and you want something that is better than your current mobile say a N95. It is expected that any mobile which has a name larger than the current mobile is superior in every way but that's not how it works.
N97 is not superior than N95 in every way, yes it is newer and shiny but the chip-set inside is not a OMAP 2420 upgrade its a samsung soc which does not have the MBX con-fig that the n95 has. The result is a mobile which has a touch screen and thus a better screen but cant do h/w 3d in any applications.
Similarly people take MHZ at face-value ARM 11 @ 350mhz vs A8 @ 300mhz who do you think will win. Different cpu's have different way of execution. If you buy a higher end mobile the cpu used inside is generally public info and we can rate the cpu's accordingly.
Now the audio processors generally mobile use h/w based on line processing units for audio and some phones use s/w driven audio processing. Generally the max the s/w freq can sample at is 44100mhz "This is generally" and h/w generally max at about 48000mhz. But phone manufactures can even max the freq level the phone can reproduce, which means a h/w max would become 44100mhz.
If we compare h/w vs s/w, the s/w would win in terms of battery consumption and h/w would win in terms of quality, but the difference is so little that it may not matter to most and the other factor for this are the speakers used.
Speakers used can be of several types, i will not go into detail "Because its too much" and i will leave them for another time.
Which mobile are you planing to get?
Which mobile do you have?
What are your priorities?