I've never stayed there myself, just lived near it in Southie for close to 20 years, right near L Street which shoots right by Summer St. where the Westin Hotel complex and the Convention Center is located. From what I understand this hotel is incredible. It's got a Reebok Gym for adults, and even a Gym for kids. It's got all updated state of the art equipment in it. There indoor pool is beautiful and their hotel lobby, which I have seen twice, when it first opened, has all these beautiful plants and trees in it. For downtown Boston's stark tall, some magnificient buildings that are basically boring lately, that's awesome news in itself, seeing all the beautiful trees and plants indoors, all year round. I know that there's a Starbucks Coffee and a gourmet restaurant in the hotel too that will be convenient.
As far as getting to downtown, where you'll want to be? This Hotel is roughly a little over a mile, may be a mile and a half to South Station. From there it's a piece of cake, you'd be able to get to the Back Bay in no time via the MBTA, the Waterfront is all along Atlantic Avenue, the North End is beyond the Quincy Market area.
Yes, this Hotel you're staying at is basically in an Industrial area, that's being all done over left and right, so you're not going to be able to walk right out your door to get to the Aquarium, the USS Constitution or Copley Plaza. You'll have to hop in a taxi or see if the Hotel provides a Shuttle Service. Which they possibly could have. If not, you're still close by to the MBTA. If you go to mbta dot com you'll see the Red line where South Station is located. There's also the MBTA bus that goes right by your Hotel, so just ask your Concierge where the bus stop is near the complex; it's probably right outside the door or right near it I would say.
The rates have been GREAT at this new Westin Waterfront Hotel. I know that the Hilton Hotel in the Financial District is always booked up, due to businesses using it all the time during the week; so this Westin Waterfront Hotel has been getting a lot more business lately.
I think it's ideal for tourists myself. It's got great amenities here; the rooms are gorgeous with flatscreen TV's, comfortable, funky brand new furnishings. I would say you're going to really like staying here. One site that you could check is Trip Advisor dot com. Go to the Hotels in Massachusetts and click on this Hotel and you'll see all the reviews on it. That's a great site and will give you a better idea on it with people that have actually stayed there.
You should try to go to the Playwright Tavern in Southie. The cuisine is quite good here.

Here's some info on it:
The Playwright
658 East Broadway, South Boston, MA 02127
(617) 269-2537
The Playwright is a classy-looking, slightly upscale Irish pub in Boston that nevertheless is very unpretentious and frequented by the locals in Southie. A full menu includes some excellent entrees at The Playwright, which is a great place to come for a dinner, a snack, or simply a few pints of Guinness
Good Luck & Have A Wonderful Time In Boston!
