Just thought I would share this new offer I saw for the Marriott Rewards Visa Card. If you do not already have it, they are currently offering two free nights as a sign-up bonus after a $3K spend: Marriott Rewards® Premier Credit Card from Chase
I'd go for the 80k points any day. 2 cat5 certs is 50k points max value, with no flexibility to use for a higher cat hotel.
So if we value the 30k point difference, at 1 cent per point (which is a fairly low valuation) you're looking at $300 extra, for $85
So you're still netting $215 in extra rewards potential.
Obviously this is all based on how you use points/certs. If you use them for a redemption that only gets you 0.4 cents per point, then that is all your points are worth. If you use them for a redemption that gets you 2.5 cents per point, you've just gained a ton of value.