I've had very good luck with US and Canadian QSL cards. My experience with Mexico is too limited to draw that much of conclusion (but lately i've been getting a fair number of them). In fact, i get ALOT of cards that i don't ask for; people seem to like to send me cards even when i check 'TNX' on my card when i know that i don't need their grid and/or state.

I'm not so good at QSLing promptly, as i record each pass i operate and then carefully transcribe them [when time permits]. But everyone gets a card from me the first time i work them in (or from) a new grid. I find that easier than trying to keep track of who needs which cards. So if you don't hear me on the air for awhile, that's probably because i have gotten too far behind in QSLing.

Here's what i do that works well for me. I print my own cards from the QSO data on 4x6" card stock and accurately trim to post card size. (Alot of folks don't want your card sticking out of an otherwise neat stack of cards.) Since i'm frequently roving, i include both my operating location, six- character grid square and GPS co-ordinates. There are a couple of graphics and some lettering is colored. Perhaps most importantly, i add a personal comment to each card, even if it's just the other station's grid square and best wishes.

In addition, as well as the usual 'Thx' and 'Pls QSL', there is also a box marked 'LoTW' which is checked whenever the QSO data has been already been uploaded to ARRL at the time the card was printed. Also, for QSLs on grid square boundaries, i often include a picture taken from QSO location, which could be compared to satellite images (such as Google maps) or topographic maps to help verify that i was operating from two [or more(!)] grid squares at once. (I probably should include the county and power level [available on LoTW] but that would require a re-design of my cards.)

The other thing i do when i want a card back is to include a self-addressed envelope and 'loose' postage. This way, the receiver can use the postage and still have the choice of using my envelope or their own. For Canada, i order Canadian stamps on-line. (I don't have a good source of Mexican postage, but i make an effort by including the corresponding US postage with the notation "for your next USA SASE". Stamp trades are welcome.) At the moment, US amateurs get an extra 1 cent stamp to they can respond conveniently even after our postal rates go up [again].

Basically, i go through a fair amount of work to produce and mail the cards (much of which was a once-only task [programming]). People seem to respond to that effort. Compared to what i've heard from most HF'ers, i am quite pleased with (and also proud of) efforts that satellite operators make to QSL. -- KD6PAG (Networking Old-Timer, Satellite QRPer)