4mb-5mbps is more than good enough actually.

I've discussed this before. Unless you rely very much on in house servers which resides on the isp's own datacentres your international site surfing is limited to around that speed even at the most off peak hours.This comes from my experience of using many fiber and cable connections around the world.

Unless you live in a country where they mostly surf their native language and surf during off peak hours, rarely you can achieve high speeds with international connectivity.That is also because they are unused.

Once the foreigner population increases in a particular area, the international bandwidth which they have will quickly be used up resulting in the same slow effect. There's no free food.

I've tried doing speedtests from many countries like Europe, US, Japan, Taiwan, Singapore and Australia. 
The people there told me don't waste your time getting anything over 10mbps because you'll rarely achieve such speeds if you're the typical internet user. So you might as well save up the extra money because it's like when you go for a buffet meal and the organizer pretty much know how much a regular can eat.

If some alternative isp is able to provide 4-6mbps average access speed in my area, I'll gladly take it up even if it were to cost similarly to Unifi VIP5 even if it's slighly slower by 1-2mbps.

Have you all heard that Starhub's 100mbps DOCSIS 3 cable modem service is not getting enough responses?Many think it's a waste of money unless you share your home with many tenants.