First stay at a MVCI. They made a point of telling me I absolutely have to checkout by 10 AM. That's pretty inconvenient but I guess it's probably par for the course at MVCIs - but will they allow late checkout if I am a Platinum elite? I'd like to at least 11 or 12 noon. If they are suppose to allow this, then I'll ask and hopefully they'll grant it.

Any other benefits? (I know they don't offer upgrades).

I found out that MVCIs do offer a Platinum arrival gift, but there is not a choice - they just give you 500 Marriott Rewards points.