Would you consider say designing an invite on MailChimp?
If you have already done something similar, what did you love? What did you hate?
The other is that paper invitations are just nicer overall. They give a feeling of permanence, are classier, give your loved ones a memento (or at least something to stick on their fridge for a while), etc.
Electronic invitations seem to me to be more emotionally distant, less "real". More suitable for ephemeral, relatively unimportant events.
I always found paper invitations annoying. I get so little paper mail I'm barely in the habit of checking the mail box. They seem to sit outside my normal flow of scheduling etc. And sometimes you have this situation where you have been verbally invited but have to wait weeks for the thing to actually show up.
I'd honestly be happier with a calendar invite. And save yourself the money on the paper.