Owen is not relevant today insofar as theology goes, but from a historical perspective I enjoy reading his books.
Owen is just is not a teacher God gave to a congregation in our century (he was given to our brothers long gone). I think some gravitate to the archaic because they think it is somehow more spiritual, however it is interesting to consider what people went through and how their faith played a part in their lives.
Let's just be honest here.
Most Christians today are theologically illiterate. To read Owens takes intellectual effort and most are simply incapable of the effort. This is true with other theologians like Jonathan Edwards. Instead, people gravitate to an easy devotional read from Charles Stanley, Chuck Swindoll, or Tony Evans. The devotionals fill an emotional void and are easy to follow.
The problem with such easy reading is that we aren't asked to exercise our theology. In becoming theologically out of shape there comes all these wolves in sheeps clothing and the sheep are too illiterate to even notice. We end up with emergent liberals like Rob Bell or open theist thinkers like Greg Boyd or fluffy nothings like Joel Osteen who simply lull people into a cozy feeling without ever knowing they are drifting toward hell. (Read the sermon to the Hebrews)
As to reading.
Go to the primary source, God's word. Observe it, question it, and interpret it. Then go to the great saints of old and see if they agree with you or if you have some wackadoodle thought that no one ever considered. If no one has that view...then I suggest you abandon it immediately. No one holds it precisely because it's wrong.
This is also where the confessions of faith come in. When we write out what we believe we measure it against the great saints of old and what they confessed. If we are confessing something never confessed before, then stop it. Go back and see what you missed because it's a sure bet you're dumber than the saints of old who wrote the confessions.
Ultimately, lone rangers today are simply arrogant people who imagine they are intellectual superiors to the saints of the past and foolishly pawn off bad theology as though it were valuable thought. A person who reads the great saints of old will recognize the puny thought of todays lone rangers and will call out the foolishness of said thought.