The quality of your cheap dsl service should still remain as high as the quality of more expensive service. The only thing that should affect the quality of your dsl service is the ability of your computer to support the specific speed of dsl you choose. The type of modem used for your dsl service will need to be up to date based and compatible with your computer. If the dsl provider you choose is unable to assure you the proper quality, or is unable to answer your questions regarding the quality of your service, you should truly consider looking into another service provider.