I just looked at the link to the Diamondback Sidekick. It appears to be a copy of the Hi-Standard Double Nine except for a better rear sight on the Hi-Standard. I owned one of the Double Nines back in the day and always liked it, if the Diamondback is as good they may be on to something, the only issue I see is that the price is a bit above the Heritage and the Ruger.
drover