i go to singapore for business and visit friends there a lot...
2) it's an island but if you live in the city you hardly ever see the ocean
4) the ocean views are destroyed by the myriad tankers (especially on Sentosa),
5) sales tax
6) and depending upon what environmental disaster Indonesia is experiencing at the moment (they tend to have a lot of them) this can affect Singapore's environment. last time i was there indonesia was having their huge forest fires so all the haze was blowing into sinagpore. the whole city smelled like burning and the haze significantly dampened visbility
7) the whole "nanny state"/"singapore is a 'fine city'", sterile, micromanaging of private lives. although the government is less nosy with foreigners
8) too cookie cutter and more rigid thinking, less creativity (though it seems like this is an issue in most East Asian majority places)
singapore pros over hk:
1) food is way better- cheap but delicious food courts all over- and great SE ASian/Malay influence so people can actually stand spicy foods there, none of this bland stuff here! also more diversity of food
2) the average person's English is better than HK- i think just on average a higher level of education
3) the average person's spoken Mandarin is even better than the average HK person
4) More ethnic diversity and integration and appreciation (there's more overt racism in HK but if you're white you will have no problem anywhere). though i've personally experienced and a lot of people who've lived in both places have also told me that on average Singaporeans are more outwardly friendly to all people, not just white people. Though I do believe HK has better laws for the treatment of domestic helpers. There seems to be more domestic worker abuse in Singapore (this is a con, not a pro).
5) cheaper rents
6) much less restrictive regulations on foreigners, such as starting a business, residency, etc.