Are you referring to the new Penguin Pro line that has the motor submersible in tank. The original Penguin has external motor and has not changed in basic design for decades except for minor modification of the box and strainer.
With the submersible motor, the Pro line claims to be quieter, but not so according to this youtube review. The self priming claim may be true since the motor is submerged, but I have no personal experience to attest it.
I run a dozen original Penguin on 6 tanks, some 30 years old, still working. I think the older generation Penguin with simpler bix design work even better than newer ones with fancy cover. I run Penguin as mechanical filter and never care to install the biowheels. One nice option of Penguin is that you can buy refillable media cage without having to pay for expensive factory cartridges. The only maintenance I need to do every few years is to replace worn out impellers that start making noise.