I am very satisfied with my decision to get Amex Platinum 9-10 months ago.

• CX Gold status. I switched most of my AC flying to CX as a results. Better lounges. Numerous upgrades to Y+ and J. I could go on and on.
• Platinum Travel Service. Quality of the agents varies a LOT, but they will book pretty much whatever I say and do no charge a fee to search out options or book. I book all my international flights through PTS now, because I am often building using routings amd fare classes I cannot buy online. I have booked lots of hotels with them, some not always at the lowest rate I could find, but I can make the agent do the work for me. Right now I am planning a bachelor party trip to Vegas. Using online rates, Vegas hotels won't even talk to me. I'd rather pay $5 more per night and make the PTS agent do everything for me.
• Fine Hotels & Resorts. I used this at a Fairmont property and got upgraded to a suite worth significantly more than the basic room I had booked. A $100 food credit for dinner and a $100 credit for breakfast, and I could use both against a ONE night stay (I stayed more nights, but the rest were at a conference rate; the Fairmont let me keep the suite the whole time).
• As many have mentioned, it is really a $499 card because of the $200 annual travel credit. I have only paid one annual fee so far and have redeemed $400 in credits due to using both in 2013 and 2014. PTS has got lots of business from me that it may not have got if I hadn't tried the service to use the credit.
• WestJet 10% discount. Great benefit I didn't know about when I signed up. I book all my WS through PTS now.
• Lounge access. Amex Platinum gets you into some nice lounges in Canadian airports now. I use the Plaza Premium Lounges in YEG and YVR regularly. In YEG even if I had MLL access for a flight, I would choose the Plaza lounge because it is always less busy! In YVR domestic, the Plaza lounge is near the WS gates which is very convenient. I've also used the Priority Pass to get into United Club lounges and lounges in Asia.
• Hotel and rental car programs I have not used yet. I have booked some rooms with SPG hotels for the summer so I will see then. Rental cars I have always found better deals other ways through other rental car companies.

Someone mentioned the prestige of carrying the card. Indeed nobody is going to care whether your card is "platinum" or gold or whatever most places these days. Due to chip and pin, even if there was cachet to having it, the stores often don't touch your card anymore so they would never know. I don't have that much money, nor act like I do, so this is all fine by me. I actually thought my previous gold Amex was the most prestigious looking card (and do recall some reaction to it at retail), with a close second being the old style CIBC Aerogold card that was actually gold and not yellow (and now black as an Infinite card).