Both the HCH and Prius we test drove were available. However they were both white. Nothing against white... But I already have a white car and didn't want another one. Didn't want my driveway to look like an ambulance bay.
I liked the HCH. I think it was more comfortable, handled a bit better and the 06 body style is pretty sharp looking. The Prius just came out with a few more things in the plus column.
Though HCH was a bit more comfortable in front (for driving), its rear seat didn't have the head and leg room of the Prius. The most frequent passenger back there is my two year old, but I didn't want adults to feel any more shoehorned than needed.
The HCH rear seat cannot be folded down for added trunk cargo area. The batteries are stacked behind the seat, so the seat back is fixed. The Prius hatchback give the car some more versatility.
It seemed the HCH relies more on its ICE for accelleration as it only has 20HP worth of electric motor (based on what I read and what the sales people told me). The high efficiency ICE isn't torquey so accelleration in HCH was noticably poorer than the Prius. My test of this was getting onto the freeway in couple places (My wife did the same on her turn at the wheel). The HCH seemed to work much harder getting from 25 to 60
mph. 0 to 60 from a stoplight doesn't really interest me.
The HCH was comparably equipped (and even had a couple of little things that I think Prius should have) and sticker priced about $2K less. But the tax credit was half what the Prius offered, and.... Honda dealers were putting additional mark up on the HCH. Carmichael Honda added $2500! Maita Toyota and Roseville Toyota (where I got my red one) were not adding any mark up. They were getting full sticker, but not demanding extra. When Carmichael Honda followed up with me to see if I was still interested, I made it clear that the additional mark up was a significant factor, though not the only one, that helped me chose the Prius.