mikeynyc,
That depends on a number of things - the key thing to know is that the IR score is separate and your 800 score on GMAT is still unaffected. It's going to be quant and verbal - same as it is now. THe only difference is that there is a 30 minute integrated reasoning section - which replaces the old 30 minute analysis of an issue essay.
You'll do 30 min analysis of argument essay, followed by 30 minute integrated reasoning, followed by the verbal and quant ~3 hrs.
As for exams after June 5 --
Do you have the time capacity to study for an extra integrated reasoning section? Between now and June 5 is a little more than a month, just enough time to take the older version of the GMAT before it changes. If you feel this is enough time for you to score well on the GMAT, then just take it now.
If on the other hand you feel there is a lot of competition out there (which there is especially with the increasing number of students scoring 700+), you can get a good score on the IR section as an additional datapoint to help you out in admissions - assuming you think you can outsmart all the new guinea pigs taking the new test.
Try some of the IR questions - see if they are "easy" for you
https://www.gmatpill.com/gmat-prep-about ... reasoning/You can also try some from the GMATPrep software and see if it is a breeze for you. I caution though that there are 4 various types of questions - so at least in that regard, it's additional preparation on your part to get to know how the question is structured and how to respond. There is no partial credit on the IR section.