This past Spring I came over from IHG where I was a multi-year Spire. Changing programs mid-year is not recommended of course, but the Marriott property density and far lower age of Marriott properties where I typically travel made it an easy decision. Spire was good for acquiring points fast for free nights, but IHG is dragging-*** on amenity matching. Spires can't even get a free breakfast at a Holiday Inn or Crowne Plaza unless the staff pulls an Oprah when you're checking in. Fortunately for me, Marriott was kind enough to approve me for a Platinum Status Challenge in late September. I'll complete it with this weekend's stay in about half the time allowed.
It looks like I'll clear 50 nights by year's end and be a "real" Platinum for 2019, as well. I've gleaned some good knowledge from this forum in the short time I've been here. If it looks like I'll get up to 65 nights, I'll be sure to book a meeting room somewhere for the last 10.
Regardless of what I get in before 12/31, I'm looking forward to getting back into the lounge at this JW Marriott on subsequent visits. I lost access this Summer after the merger because I was a lowly Gold by way of my Amex card, lol.