Depends on where you camp and what you want to achieve.
Some campsites insist on breathable groundsheets.
The PVC groundsheet or tarp will keep water out, the breathable groundsheets don't. If the ground is wet before you pitch, water will seep up. There are also two types of breathable - close weave and open weave. The open weave will allow grass the grow through if on extended camping trip, the close weave prevents that, but is not as grass friendly.
I use a Bolon close weave groundsheet, it doesn't really need fastening, but I use clingons at the door area to prevent any slippage.
A day of all things motorhome and campervan. The show is held both in the main indoor arena and across the grounds. Catering, hot drinks and food options are available. Easy access to the site and free parking included. Win one of five pairs of day tickets