Shutter counts are similar to mileage on a car - only no matter how much you baby a camera, the higher the shutter count, the more likely it is to fail.
Most new DSLRs, from the consumer level all the way through the pro end, are rated at least at 100,000 cycles (some as high as 200-250K); the cameras you're looking at were rated at 50,000, give or take, and most of the time (though not always), the shutter will outlast that estimate.
Buying one with 23,000 on the shutter count wouldn't be necessarily a bad idea or a good idea - at worst, you'd have the shutter break earlier than you expect, and you can get that repaired. On the low end, if nothing else goes wrong, you're only looking at a $200-250 repair bill. At best, you'll use the camera until it doesn't fit what you need any more, and the shutter will still be snapping until the end of its useful life.