Yes, they're fine as long as you read up on how to treat them - pick up a copy of The Art of Flowering Bonsai by Peter Adams which you can get for a few pounds. They look their best in spring (flowers) and autumn (apples), much of the rest of the time they're pretty scruffy. Don't expect good ramification or an elegant winter image, especially in smaller trees; don't expect small leaves. Do expect stunning flowers for 3-4 weeks in spring, and attractive fruit. Look for one with a garly old trunk, something that doesn't need much work for an image you'll be pleased with. Spray regularly with fungicide; give them a relatively deep pot. You'll find multiple threads about them on here.
