I was lucky enough to catch the occultation that happened two weekends ago, on May 10th, unlike most others in the local amateur astronomy community. The weather wasn't fantastic to start with, but it was good enough for Mars and the Moon to be seen through thin clouds in a pair of binoculars. Honestly it wasn't that spectacular, thanks to the clouds. The dimming of Mars took about 2 seconds, unlike the occultation of Antares I observed years ago, which saw the star blink in and out instantaneously.
That measurement can be used for a back-of-an-envelope type estimate of the angular size of Mars. Since the occultation is caused by the motion of the Moon, the angular speed of the Moon (360 deg/sidereal period) multiplied by the time taken for Mars to dim and disappear should give a pretty close estimate. The angular size, estimated from my eyeballing, is about (2 sec * 360 degs)/27.3 days, which works out to be about 1.1 arc-seconds. My planetarium program gave 5.5 arc-seconds for the angular size, so that's on the correct order of magnitude. Below average sky conditions, plus the fact the human eye can't detect a small fractional change in magnitude must have meant that the entire duration of the dimming ought to be longer.
I'm looking forward to the sigma Sagittarii occultation this Friday!
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