It is always useful when seeking advice on which PC to buy to mention it's main purpose. For example are you a game? Do you do a lot of video editing? Do you just want a decent PC for surfing,office applications and the like?
On the face of it the one from Dino PC is the better of the two, not quite the spec I would choose, but I am a gamer and would prefer a better GPU. I would also not have a single large hard-drive as if it fails there is a possibility of losing everything, I instead would have either 2 x1TB or 2 x 500GB drives. I would also,in the Dino PC,up the PSU to a minimum of 500W which will hopefully cover you for any future upgrades.Also unless you will be over clocking your CPU then an aftermarket heat sink is not necessary the ones supplied with a retail CPU will be sufficient.