We ended up going to Sitka and had a good meal. We had their sourdough bread with salt cod schmeer, the honeyed mussels and clams, the beet/verjus salad and grilled sturgeon with squash reduction. The only flaw I considered there to be was showing off with too much verjus.
All of the food was good, if not quite haute cuisine. And you are right, the service we got was great. I have some small quibbles with the execution of the service (cold plates, tiny top that could not accommodate more than one dish and wine bottle), but not the server's fault. I liked the wine selection, and its prices were comparatively reasonable. $135 with wine, $95 without.
In the end, what decided it for me was Rionne 13 calling me TWICE the day before, DEMANDING that I again reassure them we would be coming. Given the way we were treated on an earlier attempt to go into Stowell's Ego, that's it for them. Raskin's review didn't make the decision any harder, thanks!
I'm a big fan of Sitka. Here is a fawning review/propaganda piece I wrote two years ago. http://chowhound.chow.com/topics/760116 I've been back two time I think since then and remain bullish on it.
Certainly S&S has its detractors. If one thinks that a committment to seasonal/local is too limiting come winter, or if you want large portions, it probably isn't the best choice.
I have not been to Rione, though I do like Roman cuisine generally, and the menu seems to feature some of the greatest hits. Regardless, for me, since the demise of Union, I just don't consider Stowell restaurants on the same level of creativity as Dillon's. Though I do like them.