All the Askoll based pumps are quiet. Red Dragon, ATB, MSX, or a regular Askoll. They are not all pricey.
Internal and externals both have their ups and downs.
Internal use space in sump, are simpler to install. They are always water cooled and will add heat.
Externals take up space in the stand, are more complex to install, are better for high head, can be water or air cooled. Externals have less maintenance since the impeller magnet is not wet and wont have calcium buildup.