In general for me it depends how good your banner looks, or how strong your anchor text is for your text ad. You can have a great site but have crappy banner ads or ineffective text ads that don't help you at all.
Text links make 80% of the sales as they are incorporated into the copy of the page. That said banners are used for branding and can communicate much with limited animation. I keep banners at 2-3 frames with the last being a call to action.
The banner ads and text ads both, have their own qualities that can boost online advertising.
Both banner and text ads should depend on what is the objective and what is the niche of the campaign. Banner ads is used for branding