The entire history of amiga there were two types of people:
1.Who said that the bulit in amiga sound hw is good for anything, so not worth to disturb.
2. People who think that paula is a good hw but its got many limitations so after some time it must be replaced.
When i first realized in the early '90 that the new amiga (1200) will not be shipped with advanced paula (8ch,16bit etc) as commodore planned, i dissapointed very much.
As time moved on, and ahi appeared, most of the new games and apps use the advantage of ahi. so you can change your sound hw.
So the options:
Delfina : unique amiga hw, with mp3 decoder. 16bit. AHI support. good quality. You need clockport. Or clockport adapter.
Sound Blaster128, Audigy. Sb128 can be used with pci board (mediator etc) 16bit, ahi support, good quality.
Audigy: no full drivers, if can be used better quality than sb128.
terratec: similar to sb128 but a little bit better in noise-signal ratio.