They seem very similar, minus the discussions metaphor Basecamp has (looks like documents/tasks are expected to be enough, with the documents being uploaded or created via wysiwyg editor).
One nice difference is Basecamp no longer offers a free plan, which although it's not obvious from their page, Siasto does. I'm a bit early on in my current project to start forking over $20/mo for a PM tool, but I do love the new Basecamp UI...
15 days free trial doesn't seem to be comparable with a free plan... either that or there's actually a free plan but not mentioned anywhere other than "Try Free".
Yes, we should definitely make this more clear: Once your free trial expires, you can continue using Siasto for free with however many teammates you want, but without the features listed in the paid plans and a more restricted space limit.
One nice difference is Basecamp no longer offers a free plan, which although it's not obvious from their page, Siasto does. I'm a bit early on in my current project to start forking over $20/mo for a PM tool, but I do love the new Basecamp UI...