Agreed: the jump from 150k/wk to 240k/wk is pretty steep. The only silver lining is that it now makes the MVCI's Travel Package-eligible, whereas they weren't before.

I've never had the late-checkout issue before, and the MVCI's I've visited have generally been cool with early check-in. Usually they'll offer a choice if our preassigned unit is not ready - we can accept a clean unit that isn't in as ideal a location or whatever. If we ask to stick to our original assignment, the front desk seems to do their best to send housekeeping there straight away.

As a MR elite, my experience has been that they always assign us a "good" unit (that's why we're usually willing to wait for it). I've never received a full-category upgrade though. I'd always book what you need, even as a Platinum. I've never received any kind of welcome amenity. Five bucks' worth of Marriott points hardly matters, but I'd definitely notice and remember a nice touch like a snack or bottle of wine.