I started out using Marketo years ago and while I was a power user and loved the depth of features, others in the company found it to be complex and most could use it for only the basics.
I moved on to Pardot and I really liked it, and I even attended their user conference three years ago in Atlanta - which unfortunately, was when they pass along the news to customer that they have been acquired and would end up Salesforce's portfolio. Pardot was moved into their Sales Cloud (and ExactTarget went to the Marketing Cloud), and the result has been, other than some UI improvements, almost no innovation at all... and a major rise in costs, where it's extra for phone support, they charge for Salesforce Engage, they charge for Wave Analytics, etc. etc.
Meanwhile, Act-On has been the steady player in the market that has continued to advance - and you see that in Forrester's Q4 2014 Wave report where Act-On moved to the upper, Leader quadrant ahead of Pardot and HubSpot (though, I'd say that HubSpot has always been more "Movement-First" versus "Product-First" where they invest more in their marketing then their marketing features, particularly with their focus on their CRM now).
Act-On received a large round of investment money, brought in loads of new talent on the executive team and down, and continue to push out new features faster than others on the market. They were first to launch Account-based Marketing, their Social tools are very advanced (Forrester scored them higher than HubSpot for example), built Data Studio that allows us to push to our BI easily (Tableau), they overhauled all of their composers (email, landing page and forms), added dynamic content & personalization features, and added a unique way to create Program Templates that is awesome and now have a growing library of templates you can grab and use that build out all the nurture program steps for you automatically (including sales alerts, CRM campaign updates, basic or advanced if/then scenarios, etc.).
I've always thought that price should not be a big driving factor for which tool to use. But, their Active Contacts model allows you to pay for what you use, versus the size of your database - and where Marketo and Pardot are adding more modules, Act-On includes everything in their Enterprise edition. And their Support is also fantastic.
Don't be fooled. This is an advanced tool that medium and large companies are using.
Sincerely easier to use than others on the market, great overall feature set, love the dynamic content options, program templates were a game changer, account-based marketing provides visibility into how programs are doing at the Account-level that we haven't had.
The UI is slowly being overhauled but I'd like to see this go faster. Their out-of-box reports aren't great, but I haven't run across a marketing automation platform who has great reporting (I do like Marketo's Opportunity Analyzer report) and we use Data Studio to simply pull data out the way we want it to populate our reports in excel or Tableau
Value for money
Ease of use
Likelihood to recommend: 10/10