I've had the card for 3 years. The MQM boost helped me reach Diamond my first yr, and Platinum for the last 2 years. I use the club access very frequently as I almost always connect through ATL from my home airport in CHS. I've only used the concierge service once, but the time I did, they helped me score last minute tickets to "The Book of Mormon!"
I can't say for certain that I am higher priority than other Platinums because of the card, but I usually score upgrades 75% of time on T class tickets.
I'm very happy with it!