Yup, the main issue is the chloramines. As far as a homebrewer is concerned, they basically can't be removed by techniques that work for chlorine (i.e. carbon filtering, boiling, evaporation, etc.). You can force it to sediment out with use of campden tablets and then siphon your clean water out to use, but I prefer to add as few "foreign" elements as possible to my beers. I try to use campden tabs only when I'm sterilizing a fruit must (even then, I try to use high-proof alcohol to sterilize when additions are small).
The city water here is variable - with a natural water source, they have to alter their additions seasonally, so I don't want to be hassled with calling every time I brew and just buy a consistent brand of spring water (had a solid water report and has given me good results thus far).
Unless you're getting ready to start messing with adjusting your water chemistry with salts and acids, skip the RO water. Depending on the quality of the company filtering it, RO water should have pretty much everything stripped out of it. Including all of the trace minerals and elements that are needed in the various steps of the brewing process. RO water is usually used in brewing for two reasons: #1 - to dilute brewing waters that are too high in a particular salt or adjust pH; and #2 - to start with a clean water profile and manually add ALL elements and ions desired (quite an advanced brewing technique with a lot of cross-factors)