The most common feature I've found in successful tech products is ease of use. For this, a product should be intuitive. My definition of "intuitive product": -

The most common feature I've found in successful tech products is ease of use. For this, a product should be intuitive. My definition of "intuitive product": - Simple, but useful: it must possess not too many parts or features, just the most useful ones. - Familiar, but innovative: the features it possess must look like other features from other well-known products, but have recognizable improvements also. HTH ;)