Your guests will notice. I always notice, and I wrinkle my nose at it. Yes, I sort of judge when you want people to make travel plans to come to a wedding, buy you a present, and you can't even hand-write their address on the front.
If you're using the guest list manager on TK, go to "View Summary" in the light blue box near the top (next to where it shows the number of invited, accepted, and declined.) From there, scroll down to the bottom where it says "Lists." If you're providing a list for printing the invitations, you might want to export the list by "Party" and "Invitations." That will export it into an Excel document.
We had our invitations pre-printed using the same color and font as the invitations. I think it looks a thousand times nicer than the ones we had to write by hand (because we didn't have the addresses in time to send to the printer). We have had several compliments on how nice they looked - but honestly, it didn't save THAT much time once we typed in the addresses, checked and double checked them, etc. It was definitely more of a cosmetic issue than time-saver for us.
Re: export address list
We had our invitations pre-printed using the same color and font as the invitations. I think it looks a thousand times nicer than the ones we had to write by hand (because we didn't have the addresses in time to send to the printer). We have had several compliments on how nice they looked - but honestly, it didn't save THAT much time once we typed in the addresses, checked and double checked them, etc. It was definitely more of a cosmetic issue than time-saver for us.