Experience with CVENT, Certain, or other Event Platforms

We use Cvent for our annual Planview customer conference:
Horizons – The Planview Customer Conference - Event Summary | Online Registration by Cvent

I was involved in setup and skinning it to match our website and it was fairly easy. We've been using it for years and this year was the first time I had to login to make content and design updates. It was a bit tricky trying to find some of the pieces of content to edit, but I found everything I needed to. We have not purchased the additional integration to push registrants into Marketo because we feel the extra cost isn't worth it for our event.

Sched.org is another live event-related platform that we're using as an agenda builder this year.

Event Schedule & Agenda Builder App | Sched

It has some really nice features like digital signage, mobile apps, respsonsive embed code for websites, printable agenda, custom agenda builder, and ticketing through Eventbrite.

Of all the event tools I've investigated, Cvent seemed like the best deal and feature set to integrate with marketo.

I don't know about some of those on site questions about badge printing though.

I've had a good exp with them w/o marketo too.

That's quite a wishlist of features there!

I've used DoubleDutch pretty extensively (deployed to a dozen-plus live events with attendees as low as 60, high as several thousand) with Marketo and was happy with the results in terms of tracking activity/engagement, but the payment processing/limited time discount pieces have always needed either web backends or a digital POS set up (if allowing people to buy from a booth instead of, say, the app.) I'm not sure if you'll find something out of the box that does it all.

EDIT: I should also add in terms of badge printing/registration tracking, you'd probably want another standalone package, but it's not that difficult to make something in-house to handle badges if you plan on running events with any sort of regularity.