Embedding Forms on Website Versus Marketo Landing Pages

This article has a good overview of form embed vs a Marketo landing page:
revenuepulse.com/implementing-marketo-forms-on-your-website-whats-best-for-you/

Embedding is nice because it gives you better ability to control how the form renders, how it's sized, etc. Also, with embedded forms, Marketo still gives you webpage, referrer, and querystring information, so you should be fine to create campaigns per specific landing page. The only thing you'll probably have to worry about is using code on the page to define the follow-up page, since that's form-defined with Forms 2.0.

One major drawback to highlight when not using Marketo pages is that you lose form prefill. That is one thing that pushed us to create specific things in Marketo pages vs embedded. 

Wow, thanks! All good points.

If we were to embed into iFrame instead of using a Marketo landing page, how would you go about setting up a trigger in a flow? And would the pre-fill function still work?

Thanks for your help!

Yes, pre-fill function would still work, as long as you put the form on a Marketo landing page and then iframe that page into your site. Then, your trigger would just be for a form-fill on your Marketo page.

One minor nuance to be aware of: When you embed Marketo forms, there is a slight chance that some people/respondents are able to bypass the required fields. Although the amount of times this happes is very few, it does/will happen. We found that outdated browers and Macs were able to override required fields when embedded using iframes. Something to keep in mind especially/know about embedding. 

I think the other thing to consider when evaluating embedding vs. marketo pages is the user experience. If you're keeping them on your website (IE when they access the asset, they're not leaving your webpage) then it makes more sense to embed. However, if they're being directed to a Marketo landing page after filling out the form, the user experience was better sending them to a Marketo landing page first. We experienced higher conversion rates embedding and keeping them on our website, but that was when we discovered that some people were able to bypass the required fields. When we switched some pages over to Marketo landing pages, we experienced a slightly lower conversion rate, but didn't lose any lead information in the process.

To make life easier, use a Marketo Page whenever you can.

Embedding forms loses prefill and progressive unless you add javascript/jquery. In which case, you might as well use the API to customize the form on your main site.