On my way to Boston
Love great food and don't know how to choose my day and night dining. staying at the Westin and am intrigued with many restaraunts I've read about.
Please help me decide
9on the park
Justdon't know whatto decide
You really can't go wrong with any of those choices. The only thing I'd point out is that Sage is quite small and Aquitaine's tables are kinda jammed. Personally I'd go with Ambrosia, Mistral (both easy to walk to from the Westin) and No. 9 Park (which would be a pleasant walk one way at least on a nice nite).
Some clarification is in order.
"9on the park" could be confusing. I'm sure you mean No. 9 Park, which fits in the level of quality and price as your other choices. However, On the Park is an excellent neighborhood restaurant, much less expensive but highly regarded.
I'm just concerned that you end up where you intended.
IMO I'd put Mistral at the top of your list and remove Hammersley's from contention.