I will report back on the Diamond sitting room vs. Voyager suite.
In all honesty, a balcony is really not uppermost in our selection of a suite. We are looking for the most economical way of sailing on an upscale line, such as Radisson. We don't feel the need to have a balcony.
It was a wonderful perk to have it on Voyager and we sat outside several times. However, if the cheapest suite was one without a balcony, that would have been the one we would have chosen to book.
On Navigator, we chose the cheapest suite, which was just perfect for us. We were out and about so much, that it didn't matter, whatsoever.
As I said, previously - We are just thrilled to be sailing on Radisson, regardless of suite and whether or not it has a balcony or not. Cost is a definite factor. What we save in upgraded suite costs, we can spend on excursions, etc. It's a trade-off for us.