The Costa Rica is pretty above-board and straight forward. It reminds me of someone young, with a lot of energy and exuberence, very talkative. The kind of person who bounces around the room. The beans are clean looking, pretty regular in size, sort of a light blueish green in color. It roasts along in the popper pretty rapidly, spewing chaff like there is no tomorrow, usually taking somewhere in the neighborhood of 15 minutes to get a nice sheen.
The Sumatra, on the other hand, is crotchey and cranky. The first pop is fairly anemic, and you really have to coax it along. I pulled the loads I did this morning at about 18 minutes, but I probably should have pushed them a little longer. The beans are a dark olive in color and are very irregular.
I think part of why I see them like this is also the difference in flavors - the Costa Rica tends to be brighter and more acidic, what I tend to think of as 'high' flavor. The Sumatra is a good deal earthier, with lower, darker elements, mellower and stronger both.
So the Sumatra is sitting in the corner of the room, mostly keeping to itself, while the Costa Rica is bouncing around, talking to everyone at a mile-a-minute pace...
Anyway, note to self is, don't get impatient with the Sumatra.