Yeah, plastic pipes are great for beggining pipers and for people who travel and need a reliable and good sounding set. I play a set of P1's and I have been for as long as I've been playing wich is about 3 years and I have had no problems with them at all.
Now the chanter that comes with them is something to be concerned with. Dunbar is definitely not renound for their chanters. The high hand tends to be a bit wonky with any reed that you put in it which, for a begginer, is not a very good set up.
A good alternative to that chanter is a Shepard of MacCallum chanter. I happen to have all three of those and to be quite honest, there is an amazing difference between the two and the Dunbar.

But as for plastic drones, there is absolutely nothing wrong with them. They are durable as hell and they stay in tune once you get them that way. The other thing is that there is very little maintenence if you get the O-Rings as opposed to the hemp.