I don't have the lens, but references give the image circle as 270 mm. The 5x7 needs about 210 mm so it should cover with some movement. Commercial Ektars are Tessar type lenses and sharpness and quality control on the glass is considered excellent. If you have problems, I would suspect they would be from a well-used Ilex shutter.

Image quality is likely to be a little less contrasty than modern lenses, and it is single coated rather than multicoated if that makes a difference (it wouldn't to me). I don't really consider an Apo-Ronar to be a modern lens even though they were manufacturered recently; the design is old.

Steve