All other irc clients are only connected to the network as long as you are online. IRCCloud provides a bouncer by default, i.e. an irc proxy that maintains your presence and logs all chat. Said BNC remains online for 3 hours by default, papering over connectivity losses, or for a small fee of 4€ per month, you can remain online forever (good for travels and such).

IRCCloud has the ability to embed pictures, youtube videos, vines, etc straight within the chat window.

IRCCloud offers an option to keep idling in a channel even when the user is not connected. This way no conversations or mentions will be missed while away.

Files can be shared simply by dragging and dropping them into a channel. They will be hosted on IRCCloud's servers and linked.

Offers bounties for reporting security bugs through HackerOne.

IRCCloud has a simple two-pane interface with a chat window on the left and server and channel lists on the right. It includes colorized nicknames to easier tell users apart and allows customizing details such as clock format, usermode symbols and alerts.

IRCCloud will suggest putting long snippets of text on pastebin and link that instead of flooding the channel.

While IRCCloud is generally a subscription service, a limited free tier is available. It's limited to 2 external IRC networks besides irc.irccloud.com, accounts get disconnected after 2h while no frontend is used (does not apply for the first 7 days) and 100MB file sharing limit as well as it lacks a number of team and enterprise oriented features.