I've maintained PLT at SPG and Marriott for the last 8 years. Marriott because they have properties just about everywhere, unlike Hyatt and others. And SPG because it's been easy to keep PLT with 25-30 nights (after MR's tough 75 night threshold), their previously-unique nearly always available award, and now the enhanced benefits they just announced.

Both now have lifetime status, and added bonus. I'm gold on both and have about 2 more years to hit PLT on both. It's good to have that end-game in sight, even if it's far out on the horizon.