Top-Tier is typically = wider known, higher traffic sites. They are very selective in the content they publish. With our media connections built over the years, we have successfully helped hundreds of clients share their expert thoughts/opinions in top-tier media. Mid-Tier will be more niche sites or industry specific publications. If you were to compare publications to influencer marketing - think big time influencer and micro influencers. Both have significant value and should be part of an outreach strategy.