I really like those self seal envelopes. I honestly dislike the one you have to lick and stand the chance of cutting the tongue not to say the amount of germs you may be passing to the receiver of that envelope too.
The envelopes close easily and one can print addresses on them from the printer w/ no jamming problem. My only concern is that the sticky part of the seal does not go all the way to the edge of the flap thereby leaving a gap into which the corner of another piece of mail might get stuck or that processing equipment might grab and rip open the letter.