A plug in Insight would have probably sold better than the Clarity. I couldn’t make it past the partially covered rear wheel on the clarity.
When the 10th Civic came out, I was underwhelmed on our local/non-highway test drive. (I also grieved the loss of the flat back floor I had in the 8th Civic - I guess that'l never come back now). I'm guessing mid-gen revs to the 10th has helped to boost sales, with some of the features shared by the Insight (headlights) that the original release got dinged on. I still have trouble distinguishing Civics from Insights from the front (let alone Clarity/Accords).
I was somewhat intrigued by the PHEV Clarity offering the possibility of electric local miles (though needing some sort of charging infrastructure for our condo building), but I was not in the market to buy new and the reviews proved poor. Limited availability, restricted test drives to only serious buyers (only one was in the showroom), and that didn't help things. I can only think that the experience with the Clarity pointed the way to Honda what buyers wanted.
With the Insight, we were able to test drive - but it was a drive around the block! Though quiet it was, even Civic driven around the block would have been quiet. (Salesperson could have been trying to keep us from hearing the ICE grumble) I think in the end, high MPG, and reviews put me on the watch for a used model. When I test drove my Insight - I took it on the highway due to concerns about power and noise - I found sufficient power, but it didn't think it was particularly quiet. But a good looking sedan and high MPG, were what I was looking for and I think setting recommended air pressures has helped in terms of road noise.