It's almost impossible to judge based on the pricing alone. Paying top dollar doesn't guarantee anything extra and low prices don't always mean low quality service.

$6.99 looks like a first year discount at dynadot with renewals at $10.88 USD.

> Why such a huge difference?

A lot of registrants don't know what the wholesale pricing looks like and the difference between $10 or $25 / year for a business isn't a factor. The risk that comes along with transferring to a cheaper registrar isn't worth it to save $15 / year.