In your opinion, which water town is better to visit on a day trip from Shanghai: Suzhou or Hangzhou?

I recommend Suzhou more. I visited Zhouzhuang Water Town in Suzhou and it's fantastic.

Actually,now chinese people will not choose zhouzhuang,coz it was the first watertown exploited as a tourist destination,so it is too commercialized.Well,every watertown is commercialized,and very crowded.
My home town is Wuxi,just about 60 km to Suzhou,and I have been to nearly all watertowns.
Tongli is my favorite,the Tuisiyuan(退思园）,a garden in Tongli watertown, is very beautiful.
And I also like Xitang(西塘）,in Zhejiang province,while perhaps Wuzhen(乌镇） is more famous because of a TV series.
Mudu（木渎）is also very good,you can take a bus from the suzhou railway station,about 45 minutes.It is not as crowded as others,but very beautiful,2000years ago the emperor of Wu state chose this site to build the palace for his favorite concubine,Xishi,one of the four beauties in chinese history.
And there are also many others,like Luzhi(甪直）(near suzhou），qibao（七宝）,zhujiajian（朱家角）（near shanghai，qibao is accessible by subway from shanghai downtown),and nanxun（南浔）(in zhejiang)
I think just one is enough,in my eyes,all of them are the same.
I think suzhou is a good city for traveling.There are many gardens,and each is unique.Zhuozhengyuan(拙政园）and shizilin(狮子林）are my favorite.they are not far from each other,15 min walking.Zhuozhengyuan is the most famous and really full of historical stories,and shizilin is famous for the rockwork.

Thank you very much for your response. It helped me a lot.
Regards.