For anyone searching for the audio gains to be obtained with 24 bit playback, I have found the ideal app. Namely Deadbeef. It will also upsample 8-bit to 16 and 16 to 24 and sounds much better than Amarok etc, I have used in the past. You will need a DAC capable of handling this though of course! Mine is an M-audio 24/96 Audiophile.
I tried installing Deadbeef from the Opensuse repositories but it wouldn't play so I downloaded the tar from their website. If you do it this way it is really important to read the readme file. Very important is checking the plugins that you need will be installed so run ./configure and check that there is a yes next to them. If not look for the apps, devs and necessary libs and retry ./configure until everything looks good to go.
The sound is so much improved I can't recommend this enough. I'm thinking of buying an Arcam irDAC later in the year (mainly to improve sound of dvd and blu-ray) so hopefully it will play nicely.
FOSS the new way forward.