The envelopes seem to seal properly and the paper used in them is good enough quality to withstand the postal system. However I guess I'm old fashioned and still prefer the closures you had to lick because I believe the seal is tighter and more secure.
Better than having to lick. Although I have noticed once they get a little old the adhesive doesn't always stick well. That's the only reason for four star.
I always buy the easy close envelopes at Staples. I buy them on sale and they are a very good value. I serve as secretary for my church district association and have to send out several letters a few times a year. I use these envelopes for this task as well as personal use.