Almost all the online payment service providers are reversible.
LocalBitcoins could be a great alternative. You deal the seller face to face and use hard cash.
Much safer than reversible transfer services.
Unless It's done right and in a public place, things could be even worst then dealing with a reversible payment method. Bitcointalk reputation system is not that easy to abuse, I find it a better indication of trust then Localbitcoins, so It's better to trust with members around here.
I see, in that case, what could be the easy and safe way to get in tough with such sellers with good bitcointalk reputation?