Piping

I talked with a plumber that will be doing the plumbing in my new bathroom. He recommended using plastic pipe rather than copper for the water supply because it would be faster to install.

What are the advantages/disadvantages of plastic pipe over copper?

Price is a huge factor. The price of copper has gone through the roof.

I'm guessing you are being quoted PEX.
It is a good material that is very easy to work with and in some aggresive water conditions Would be a much better choice.

Copper pipes are the Caddy of pipes and probably will be for some time but its cost is way up there now and under some conditions deteriorates rapidly.

Pex

The advantages are that it is cheap and faster to install.

The plumber says plastic. The people here say PEX. They are not necessarily the same.

The plumber may be talking about CPVC which is much less expensive and would not get a lot of support from people here.

Ask your plumber if he is proposing CPVC or PEX, and get him to give you the price for each to make sure the "saving" is putting money in your pocket.

If he is suggesting a change order to go to plastic then you must be sure that you are getting the benefit of the saving.

I.e, most people think pex is superior to cpvc.

I appreciate all the responses. The bathrom I am installing is on a 3rd floor of a single family home. Will there be a significant amount of heatloss from the basement to the thrid floor if I use PEX?

There's less heat and friction loss per ft with pex than copper.