The KJV is a great translation, my personal favorite by far, though when I first started reading it I had to keep a dictionary handy, it was well worth it. The language is beautifully written and full of all the Power of the Word. I grew up reading an NASB, and let me tell you, when you get used to a version and all of the "key words" for looking up verses to find a matter in a concordance, it makes switching to another version difficult, but the switch was well worth it for me personally. There really does seem to be a difference for me, I've actually started reading my NASB a couple of times recently and put it away cause I felt like I was getting cheated
The reason I started using the KJV was for apologetics, cause alot of people won't even discuss things with you when your using a different translation, so for arguments sake I switched, cause it didn't matter one way or another with me which translation I used and I'm educated enough to look up words I don't understand, but much to my surprise I am very happy that I did switch. It was an unexpected blessing.