Well, as everything out there, it depends on your needs. But I can assure you that Marketing wise, with Clickfunnels you can do the following stuff:
Allows you to generate and capture leads providing powerful converting pages (opt-in or landing pages) to nurture and grow your email lists.
It can be integrated into your custom domains.
It helps you build robust Sales Funnels easily and fast by providing tested and proven Marketing Funnels to increase conversion (Sales).
It comes with many FREE proven funnel templates for any niche (as it is entirely focused on Marketing more than on one particular niche).
Comes with a built-in Email autoresponder (in conjunction with the full suite plan) helping to easily generate email sequences for your lists.
It can be integrated to many other tools, email auto responders and even other page builders or CRM solution (Customer Relationship Management) like WordPress.
Provides a built-in split testing tool allowing you to try out different landing pages and select the best converting one.
Shows conversion stats so you can compare different offers for the best converting one.
It allows to share the funnels you build within the tool, in the case you want to build funnels for clients or offer DIY (Do It Yourself) Funnels to share (generating Affiliate commisions, explained further down this post).