My verdict: powerful for the US market, but very expensive and less effective in Europe.
Clearbit is good especially for those targeting a US or international market. Data is complete, integrations are excellent.
It's much less effective in Europe. I don't necessarily recommend it: it's very expensive. But if you want to directly target an international audience, it remains a reference.
What I like less: opaque and very high pricing, reduced effectiveness on the European market. Since the HubSpot acquisition, the product strategy is less clear.
My advice: if you target the US market with a substantial budget and use Salesforce/HubSpot, Clearbit can make sense. For the French market, look at Dropcontact. For international at lower cost, explore Datagma or Apollo.