The analogy we use in our house Iamboatman that is similar to your fish/steak choice is that's why there is chocolate and vanilla ice cream. Some days you want chocolate, some days you want vanilla and still yet on other you want both
Allison, DH and I both said that in a perfect world for us the suites on SD would be the size of SB's! It's all about trade offs (see ice cream analogy above).
I agree that SB is a good value for the money ... especially since SD's prices has increased quite dramatically in the last year or so. We paid about the same for this year's SB cruise as we did for last year's SD cruise. We are looking at our 07 cruising options are you are right that SD is significantly more right now than SB.
We have sailed RCCL's Navigator of the Seas as well. We were in a junior suite on Deck 10 with a balcony and we spent a lot more time in our suite and on our balcony as there were thousands of people on board. On SD and SB, with no balcony, we spent most of our waking hours on deck ... with 100 people on SD and 200 on SB.
We sail the mass lines with our 14-year-old DD ... and we know going in that it will be a completely different experience that sailing on a luxury line.
It's all about choices ... I agree Iamboatman that it is wonderful that we have so many cruising options from which to choose.