I have a Diamondback DB9 and use it as my every day carry. It is easy for me to carry and I like it. I've put about 300 rounds through it. This is not a range gun!
I have discovered that it doesn't like to feed a hollow point from a fully-compressed magazine. But, it will feed ball ammo from a fully compressed magazine with no problem; and hollow points after one round is eliminated. So, I use one ball-ammo round as my first round in the magazine. All other rounds are hollow point, including the one in the chamber. This works for me.
Also, this particular gun fits perfectly in a little pocket holster that looks like a wallet, which also works for me.
You will hear some people complain about the DB9. I have to wonder if anyone who I have seen complain about it actually carried it and tried to make it work reliably. It is not a Glock. It is picky about what ammo will reliably work in it, however, it can be a very reliable gun.
I traded my Ruger LC9 for the DB9, because it's just easier for me to carry the DB9 than the LC9. My LC9 was also very reliable and was a good gun.