"Great schools" is an opinion, which should be left out.  If the schools are actually ranked as top-rated schools, who rated it as such and is there statistical evidence to support it?

While it is not an MLS rule violation, and likely not an ethical issue to say top-rated schools, there is a risk that someone could claim false advertising (unlikely but, nevertheless).  It would be better to name the schools for which the property is zoned and let the buyer agent and their client do their own homework on whether it is a top-rated school or not. Listing agents and sellers need to remember that there are a lot of buyers that do not care about school zones because they may send children to private/magnet/charter schools, and some buyers will not have school-age children.