[rajeshpatel15]

Depends entirely on your use case. Mailchimp is solid for marketing automation and small-medium businesses, but 'best' varies significantly:

For developers/transactional: SendGrid or Postmark dominate with superior APIs and deliverability rates (99%+ inbox rates).

For enterprise: Salesforce Marketing Cloud or HubSpot, though expensive.

For price-conscious startups: ConvertKit or EmailOctopus offer 90% of Mailchimp's features at fraction of the cost.