The quality of vinyl fence (thickness, UP protection, finish) varies between manufacturers. My experience has been with 4-rail horse fencing. The stuff is very strong and can be made extremely strong by placing a re-bar rod down each fence post and filling the interior of the post with concrete (1/3 to 1/2 height is adequate for a big strength boost). If you add concrete, the posts become incredibly strong. Although the field fencing will flex it rarely pulls out of place, but if it does, just put it back. I have not see the stuff break.
The reason for using vinyl is a fairly easy installation and never needing to paint. It will outlast 3 wood fences, and will never rot. What brand are you looking at? Many offer web sites with precise installation instructions and warranty information.