It is a norm now before you buy a piece of equipment you'll do a research on net.
But anyone can post a review online including a team of marketers hired by the manufaturers to give themselves great reports. Who can you trust and which report can you believe?
I bought a Sigma 18-50 mm F2.8 lens after doing my due delligence on the net. But I found out it was not as great a lens as what those reviews made it out to be.