This topic has been covered before - here's a summary:
Everyone (who expresses an opinion) thinks that copper is aesthetically better.
Most people think that copper tube lasts longer than the plastic equivalent. These people have not yet responded to my requests for objective data to support this view. Some plastic pipe is guaranteed for 50 years. Copper is not.
It is a fact that copper is more rigid, and requires less clipping.
It is a fact that plastic pipe has a smaller bore size, often leading to higher water flow rate. I've never heard of anyone carrying out a scientific study to produce objective data, but the higher noise that might result from the faster flow is negated by the smaller number of couplings and sharp turns that would be needed with copper pipe.
Most people think that push-fit fittings are more expensive than the brass equivalent. This is sometimes true and sometimes not. If you factor in the cost of the labour for installation, it's a close call, but pushfit is quicker.
Plastic pipe is infinitely quicker [than copper] to install over long runs, through joists, within walls and floors (within conduit of course), around corners, and it saves on the number of flow-reducing fittings that are deployed.
There are cases of rodent damage to plastic pipe. It is wise to avoid plastic pipe where rodent attack is considered likely.
All plumbers encounter leaks in copper pipe and brass fittings. Some claim to have splits in plastic pipe and leaks in push-fit fittings. Like HarrogateGas, I've never had a leak on any push-fit fitting that I've installed.
Some people believe push-fit fittings to be easy to install; too easy in fact, such that they perceive a stigma arising from the use of these fittings by less-than-competent tradesmen and DIYers. These people allow ego to cloud their judgment by refusing even to consider push-fit and/or plastic.