Pros // No need to think of something witty/punny/sweet - because they do it all for you!
Cons // These can feel somewhat unoriginal, forced, or impersonal if you select a card that isn't necessarily, say, the best fit for your recipient.
Pros // You can write something as mushy or as straightforward as you want, exactly as you want to without someone else putting words in your mouth.
Cons // If there's so much you want to say, this could take quite a while to write!
Do you usually give Hallmark cards or handwritten letters?