I spent about 3 months each as Gold and Plat this year. The only perceived benefits of Plat over Gold were the extra mileage bonus and higher priority for standby.

Of the other benefits...
- I got "Priority" tags on my luggage but the bags still seemed to come out in random order.
- I requested upgrades on two flights. I missed one and the other had so many F seats open that a Gold would likely have been upgraded too.
- I got very good phone service, but I also got very good phone service when I had no status.

In short, I'm not sure it's worth going out of your way to get over the Plat hump. I have one more segment to EXP, which I suspect is a different matter.