I was surprise when first started reading the esv as to how much it felt like reading the KJV, its almost like the NKJV in how it reads and sounds.I never really left the KJV, nor went to the ESV. When I began reading the KJV in 1986 I picked up an NIV as a supplement, to help me to better understand passages I found difficult.
Over the years, though I stayed with the KJV/NIV combination primarily, I began to add other translations to the mix. I became fond of the NKJV and would sometimes go to the NASB since it is supposed to be the most literal mainstream translation.
I was somewhat prejudiced against the ESV because of opinions I read on forums. The massive promotion by Crossway, the fact that it is not a new translation, but a revision of the RSV, which is a revision of the RV, which is a revision of the AV.
I finally got a copy and began to incorporate it into my supplemental reading. I was surprised at how similar it is to the KJV in many verses. So I haven't gone there yet, but I am dipping my foot in the water more and more, and liking it.