Bruce Silver wrote up a quick, thorough review of Signavio, a new BPM in the cloud offering.? Looks like it is primarily focused on modeling rather than execution, which makes comparisons to Lombardi's Blueprint perhaps the most relevant comparisons.
As usual, Bruce's sense of humor is on display ("You have to sign a click-through agreement in German to get started.? Oh well, who reads those things anyway?").
One really good shot against Lombardi's Blueprint in his review:? Signavio can export an XML document that represents the model.? There's no such facility in Blueprint (though it can "publish" to Teamworks, that isn't the same thing as exposing an XML output).? Bruce also points out that they have full support for BPMN 1.1 (whereas Blueprint only supports a subset), but Lombardi would argue that they're providing a reasonable subset to keep the diagramming from distracting from the process at that level.? (Still, like Bruce, I'd like to have the full set of diagramming options for power users).
At any rate, its? a good read, and from the comment thread, Signavio is already working on some of the issues.