The only thing you can find online is usually catering to rich western tourists or "expats" and usually boils down to "Which place is the most western/ High GDP and McDonalds!" so I'd rather get an opinion from someone that's been there that isn't a business tourist.
It's sad to see 苏州 (suzhou) characterized by its relationship to 上海 (shanghai), when 上海 is merely a city invented by China within the last 100 years to interface with the capitalist west. 上海's culture draws from the original, ancient cities of 杭州 (hangzhou) and 苏州. If history had played out slightly differently, 普通话 (common speech) would probably be their 吴语 (wu chinese) due to 南京 (nanjing)'s influence.
I did have friends who lived in the suburbs between SZ and SH and commuted daily to SH, so its current economic influence can definitely overshadow the historical relationship between the two cities.