I mostly use paper checklists, and I didn't buy a card on eBay until 2013. I guess I consider myself a very late graduate of the old school. These days I still have my lists, but I have my phone with me as well to check prices. A dealer actually said to me that it was dangerous to have my checklist on my phone because I could get hacked.
Sadly, I do not think I'll ever go back to the show I've been attending, despite the interesting characters I've met. I'm tired of walking in with $500 and walking out with $490. It's just not for me anymore. And I've often had the same problem of trying to find the dealer whose card I'm staring at - makes you wonder how common thievery is.
I've been to the most recent National in Cleveland and hope to make a trip of it this year to Chicago with a couple friends. At least there you see cool stuff - that I can't afford!