I've been told that my meeting will be in the Vishrantwadi/Kalas area. but I don't know the city at all, so don't know what is a reasonable distance away. My colleagues are interested in staying at the JW, but from looking at the map, it seems to me it might be a bit far, and the HR or Westin might be a more comfortable distance. I'll be driving to/from Mumbai, so proximity to the airport isn't a necessity.

In your case, I'd go for Hyatt Regency or Hyatt Pune over Westin. Both are closer to your area and have substantially better properties. I've been to all three, and I'd rank Hyatt Regency, then Hyatt and then Westin.
There's a new Novotel in the same area. Haven't stayed there but had a dinner once. Not too shabby.

Though Vishrantwadi area is ironically closest to Airport. :p

JW Marriott is the ONLY place I stay in Pune. In fact, I am here now!

I used to stay exclusively at Hilton properties (was a Hilton Diamond for years) , but this hotel made me switch to Marriott for all my stays going forward. Love this place!

Rooms are clean, service is friendly, the onsite coffee shop is fantastic (try the PB-chino), and the breakfast is amazing. If you are staying for more than 8 days, look of the 'long-stay' rate where you get free breakfast, a tour of Pune, airport transfers, a room discount, etc.

Ha, I sound like a commercial!