Polybutylene plastic pipe was commonly installed in mobile homes and low-budget housing, mainly during the 1970s and '80s. As you've learned from your neighbors' experience, polybutylene pipe is prone to leakage. This can occur as slow seepage at loose fittings, or as major outpouring from broken lines. A water pipe may simply rupture, causing a torrent to spew wildly within a wall or inside the attic. Surprise leaks can attack at any time or not at all. Polybutylene can waken you with a collapsing ceiling in the middle of the night, or merely worry you over an expected leak that never happens. It's totally unpredictable.
Rarely do sellers pay to re-pipe a home simply for the sake of marketing, but for some people this may be a serious option, particularly if real estate sales are slow. Your primary responsibility as a seller is to disclose all known conditions that might concern buyers, including the potential for leaky pipes. If you choose to re-pipe, that's OK, but keep in mind that many buyers are willing to assume risks that are fully disclosed. Some might insist on a re-pipe or ask for a price reduction on the property. A few, however, might withdraw their purchase offer entirely. On the other hand, you might find a buyer who was planning to remodel the home anyway, in which case major improvements now would be a wasted investment.
In the final analysis, there is no single decision that fits all situations. Re-pipe if you prefer, but if not, be sure to fully inform buyers of the inherent risks of polybutylene pipe.