Sorry, I'm afraid that really isn't enough information. I was looking for the specific Marketo platform action features: where the objects are output (emails and web pages), Segmentations, trigger and batch Smart Campaigns, how you expect to incorporate COs into canned Reports and into Smart List pseudo-reports.
Still, the partial info you've provided already makes COs seem like a worse fit. For one example, a Marketo form cannot create Custom Objects on its own (a webhook-triggered integration can do so, but that isn't native). You have to think very deeply and technically about how the account-lead relationship will be created and maintained at each entry point into the system.
Remember: you're taking the fate of your business in your hands with every martech stack/feature decision... a few sentences just can't suffice to figure out which way to go on million-dollar decisions! Do you have a complete requirements document? Have you considered working with a consultant/agency who knows the ins and outs of such stuff to create that doc and steer you the right way? I'm concerned that you're not coming in with enough familiarity to make these decisions internally.
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