Germanshepherdsmum
I have both. The oxeye daisies are much taller and have been beautiful this year but will be cut down tomorrow as they are now a complete mess. The erigeron will happily carry on flowering for several months.
Yes, it's the shorter flowering time which puts me off the oxeye daisies slightly, though the flowers are pure and perfect. I think a solid patch of the Erigeron would be lovely, though I'd have to weed the area very carefully first. I've only had it growing in old stone paving and on steps before, but haven't found it invasive.
I've always loved daisies, the larger types seem to work well with so many other flowers.