My three thoughts on the two brands:
Towneplace Suite offers a fully equipped kitchen, while the Springhill has a microwave and small refrigerator. I stayed in a Towneplace a couple of weeks ago and really enjoyed cooking meals in the evenings. Being on the road 240 nights a year, I get tired of eating in restaurants or even driving to one to pick up take out food.
Springhill provides 10 points per dollar, while Towneplace gives 5 points per dollar spent. In my mind, and again only my opinion, this is a big enough negative to stay away from Towneplace, especially for a lengthy stay. It is tough giving away MR points.
I believe both brands now offer free Internet service. When I was at the Towneplace, it offered wireless service which did not reach my room so I was without Internet for the 13 nights. Now, that was a pisser!!