Generally speaking, a good visual design for a logo is preferred. It's the quickest way to imprint on potential customers on who you are - a simple visual image will stick in their minds longer than just text. Think of the Golden Arches of McDonald's or any other very memorable logos that stick with you - they have games for this sort of thing that's how easy their logos are to remember!
I do get text-based ones sometimes, some companies do very complicated things and so it's very difficult to encapsulate them into a single coherent image.
Traditional logos, think like Harley Davidson's old logo and so on, are so complex that at certain scales they are unreadable and unmemorable, so they have fallen out of fashion, and I would recommend to go for something simpler.
Hope that helps!