RO water may vary, depending on how the dispenser is maintained, but is generally lacking the necessary minerals needed to produce good beer. Brewing with my tap water is out of the question, so I too use RO water. There are a few on-line brewing water calculators out there and any of them should get you into the ballpark.
The composition of your brewing water affects much more than hop perception. It has an affect on mash conversion, beer clarity and the overall flavor profile just to name a few aspects. Mash pH is very important as well. The water calculators also estimate pH based on the profile of the water you start with and allow you to adjust that as well. Again, most of them will get you into the ballpark.
If there is no reason to believe your tap water isn't good for brewing I'd try it rather than RO water. If it isn't fit to brew with and you don't want to get into water adjustments, spring water is usually a better choice than RO.
Good luck and happy brewing,
Bob