Long time ago *ahem*....I was offered an Amex Platinum. I took it up, but gave it up after 2 years because the subscription was so damned expensive - over S$2000 per year or something like that (if I'm not mistaken).
I never used the personal concierge services, etc etc. I just used it like a normal card. They recommended discounts, memberships, etc....but they were all at so expensive type of set-ups I couldn't afford any.
The only privilege I had with the Platinum? There was once when I was paying for lunch and my friend said "wah, nice". There was another time when I bought my foreign business guests dinner and they said "wah, Amex Platinum.....maybe you're earning too much and should give us more discounts".

At many places, I found that skin colour was more important than card colour. Angmohs using cash were treated better than me with my Platinum. After all, its just a mode of payment, so why should someone with Platinum be treated better?
In the end, I realised that a credit card was just a credit card, regardless of its name or colour.....and I gave it up. Furthermore, in Singapore, the credit limit is the same, no matter what type of credit card you have.
Now, I have a DBS platinum, but thats because it with free lifetime subscription. I also have a Citibank Gold, but its just for the frequent flyer mileage and not any other reason.....otherwise, I'd rather just get a normal non-Gold, non-Platinum Visa card.