I've had several Daewoo DP-51s and a DH40, and now have a Lionheart LH-9, which is a (very slightly) updated version of the DP-51, sold here in the US.
The DaeWoo was (is?) the issue weapon for the ROK military and a fine-shooting handgun. Fit and finish are typically pretty good, and reliability is very good. The only problem is magazines, which can be pricey -- but you can use (at least for the 9mm models) the S&W 59- (and 59xx) mags) instead. The S&W mags extend about an extra 1/8", but function perfectly. (I don't know whether then S&W 40xx mags will work in the DH-40.)
They have a unique trigger/action design. You can start from hammer down, from cocked & locked, or hammer cocked and pushed forward (to an apparent hammer-down mode.) When in this that third mode, the trigger becomes a two-stage trigger for the first shot, but it's easily managed. The safety can be used in any of the three modes.
I traded both of my DP-51s away, and later regretted it. The Lionheart took their place. The DH-40 version is a 40 version of the same gun; I didn't like my .40 model as much ad the 9mm models, but it was probably just me. (It was only years later that I really got comfortable shooting .40 handguns.)
Great guns. Some parts may be scarce, but I've not ever needed any.