Don't forget faster processor and graphic, not to mention better LCD, stereo and louder speaker than 6s. If you want good camera, should get 7+, 3gb ram and higher res LCD as well. Once you are in 5.5", you won't bother look at 4.7"

Too bad your 4s screen broken, else you can consider selling it, I did sell 2 iPhone 4 of my parents' few months back and get them new 5s, so much better even 5s in iOS9. Their iPhone 4 in iOS 7 are driving me crazy in getting the latest apps to work. The good part each iPhone 4 can get back RM400 which is not bad for a phone that is 5 years old.

It probably take you few weeks to not get use to 5.5", you won't be bother 4.7" after having it for few weeks.

Yup, they are trustable. Bought couple of items from the vendors there. Just make sure you get the correct set if you decide to buy there. The warranty should be from GemFive themselves. Don't get those with IMPORTS tag or any other vendors. However, they said delivery date is end of Oct, so well, you won't get your hands during the official launch date. RM 250 discount is tempting though, too bad no Jet Black.