Hi,there
The accommodation is not superior in Songpan, but it's economical. Generally speaking, it takes about 80RMB for a standard room. The recommended hostels are Jixiang Binguan, Guyun Kezhan (古韵客栈). Songzhou Gucheng Binguan (松州古城宾馆) and Yunlan Fandian (玉兰饭店) are also what tourists like.
Compared to Songpan, Chuanzhusi is filled with hotels, ranging from guesthouse to five-star hotels. Minjiang International Hotel (岷江国际大酒店) is a five-star one and take about 300 to 400RMB for one night. You can also find other types of hotels as you like too. One great thing for Chuanzhuzi is the convenient transport. It is not far from Jiuhuang Airport, only 30RMB for the taxi fare.
So i suggest you stay at Chuanzhusi.