What do you like best?
I'm used Marketo, Hubspot, Pardot and Eloqua extensively. I have been admin over each of these systems for the last 6 years. Having used Eloqua, the "Cadillac" of marketing automation I've got a good insight into what Marketo is and is not.
Marketo is easy to use, quick to setup and an all around good medium level tool. It does everything my company (60 employees) needs. In the past, though I did have to hack it and build work arounds frequently to get more advanced functionality out of it. In the last few years, though, Marketo seems to have surpassed Eloqua in functionality and ease-of-use.
Overall though, I LOVE Marketo and think it's a great tool for the majority of SMBs.
What do you dislike?
UPDATE 2/14/2017 - Coming back to revise this review years later as I've seen Marketo grow and improve. 2 and 3, below, are no longer a problem. Marketo has more integrations now than Eloqua (#3). The API has been greatly improved in Marketo too (#2). #1 is still kind of an issue.
Having used Eloqua, I know how nice their campaign/program builder is. You can drag and drop build your campaigns on a canvas type layout. It's great because it's easy, gives a better top down view of your campaign, and helps you display a campaigns functionality to your executive team. Infusionshoft has something similar. Why Marketo hasn't adopted a similar format for building programs is beyond me.
A few other beefs I have with Marketo are:
1. Form and Landing Page Builder are pretty bad. Marketo has admitted that these two pieces of their tool are the only remaining remnants of their original tool (which wasn't even for marketing automation BTW... Marketo's first tool was an Adwords management interface). Marketo has also said they're aware the form/landing page builders are junky and have said they're going to be rolling out new versions though they wouldn't commit to a timeline for roll out.
2. Their API is weak sauce. I wanted to bring some of our customer renewal emails into Marketo (instead of having our DEV team send them out with our in-house PHP scripts), but we need to send out customer keys (like product licensing keys) in the emails and the Marketo API didn't really have a way to do it. We had to build a work around, which after I planned it out the DEV team kicked it down the road because it'd be too time consuming and they had higher priorities.
3. The third party integrations aren't quite there yet. They've launched a "LaunchPoint" marketplace where you can go and view their partners, but sadly most of these partners do not have any integration with Marketo yet. Eloqua had some pretty extensive integrations that I miss not having in Marketo. However, Marketo has a larger market of partners and most of them are currently working on integrations, so it's only a matter of time before Marketo overtakes Eloqua in 3rd party integrations.
Recommendations to others considering the product
For most SMBs I'd suggest using Marketo over Eloqua, Silverpop, Pardot, or other marketing automation suites. i've used Eloqua heavily, and while the tool is powerful, the overall interface (even the E10 interface which I have used) still falls short of what Marketo offers. I've evaluated both Silverpop and Pardot and both of those don't offer the bang for buck that Marketo does.
If budget is a real concern to you you may want to try ActOn. I set it up for a client and it fits their needs quite well, though their needs aren't that great.
If you are a newer company and sell stuff, and don't need to use SalesForce for a CRM I'd suggest InfusionSoft. InfusionSoft is more affordable than Marketo though it too lacks some of the Marketo functionality.
All around, I'm pleased with Marketo as a tool and even more pleased with it as a company. Though I've had some limited support issues with Marketo, they are generally responsive. As a company they're doing some awesome things and applying a lot of pressure to Eloqua, as they have quicker development cycles and seem to be a more agile company.
What business problems are you solving with the product? What benefits have you realized?
In using Hubspot and Pardot in the past, I've run into major hurdles with quickly launching new campaigns and with flexibility in reporting. Marketo makes both of these tasks very easy!