Arriving on Sunday afternoon (25 May), flying out Thursday morning (29 May), first time visit.
I do like art and culture and I can see the value of the Museum Card if you at least visit the "must" museums and one or two others.
But I'm as interested in the architecture and presentation of the museums as the art works themselves. So I would see going to the ones like the Willet-Holthuysen, to take some pictures.
Also got idea from Cecile's tips page to check out the EYE and the NEMO, for the views they offer, as much as the exhibitions at these venues. (It seems you don't have to buy a ticket to the EYE to access the restaurant and the roof, though the ticket is covered by the Museum Card, while it's not clear if you need to buy a ticket to get to the NEMO roof?).
Although the Museum Card would be worth it with just 3 or 4 venues, if I got the MC, I'd be tempted to spend all my time in Amsterdam visiting museums.
So I don't know if I should get the MC or just look to spend more time outside, especially if the weather is good that week. One option may be to take a day trip to Delft, for half or a full day, though maybe there's enough to see without leaving town as it is.