The Scar, m4/16, PDW all use the same WE m4 mag. Some of the PDWs come packaged with a PDW mag, those mags aren't compatible with any other WE gun except the PWD.
That said the PDW is a great little gun, kick is comparable to any of the other WE GBBRs and as for looking more reliable, looks don't tell you if a gun is reliable or not. I cannot speak on the reliability of the PDW itself but if it is anything like the scar and m4/16 series then it is going to be a well preforming unit.
One thing to take into account is that with a gas platform most people are going for the realism aspect of the unit. 30 round mags, the blow back from the gun, ect, You will most likely be out gunned if you aren't playing a milsim game.
Mid-caps hold around 170ish rounds and low-caps are 68-70. Not the greatest numbers to have stacked against you, it just means you have to pick your shots.