I have recently swum with the new Finis SWIMP3.2G & its is much the same as the old Finis SWIMP3.1G in sound quality except it has more memory and a better designed USB cap. The colour of the new unit is black and yellow and is different from the blue and white of the old unit but I essentially think there is no fundamental difference in design except the goggle strap clips maybe slightly longer.
The sound quality seems crisper and louder underwater and has a richer bass sound, than out of the water. This is due to sound being conducted better in water than air. However I find sound out of the water OK to listen to when doing breast stroke when my head bobs in & out of the pool but that said the sound experience is a bit richer when doing backstroke or front crawl.
In sum Finis SWIMP3.2G has 2 Gbyte Memory where as SWIMP3.1G has 1 Gbyte meaning you can have a choice of around 500 as opposed to 250 songs . Also the USB cap is attached by a plastic strap on the new Finis SWIMP3.2G so its harder to loose the USB cap than its predecessor SWIMP3.1G, which wasn’t attached by a plastic strap.