Hi Suyash,
SalesforceIQ is an out-of-the-box CRM solution that automatically tracks and analyzes the day-to-day interactions that drive professional relationships. With SalesforceIQ, you can quickly connect with your Gmail or Exchange email and leverage Relationship Intelligence to sell smarter.
Sales Cloud is a fully customizable platform that can provide a single view of your customer and access thousands of applications via the AppExchange.
Hope above points will help you in making your choice.
Thanks