ok -- first off -- from personal experience -- stay away from reciprocating saws with scraper blades attachment. it has too much movement for my liking and when it does strike - sometimes it works sometimes it just jars you right back. you have to use a right balance of angle, speed, and watch what you are doing . no too dangerous.
i have used the harbor freight mini jack hammer with flat blade -- it works, but its also tedious. i used bosch sds bulldog -- it doesnt have the movement like the harbofrieght one but its lighter, smoother and softer. still tedious. those OLLLD tiles on concrete are a BEAR. you cant heat them up and then pull since concrete would suck up so much heat like heatsink it just a waste of gas. if it was on wood subfloor. if it was the newer tiles yeah comes right up with some heat.
whatever you do -- its breathing protection time since it must be one of those old tile before 80s and they use nasty stuff. IF you got a weekend of free time and you can rent a floor scraper, you can stand up ad abuse the heck out of it since its old tiles on concrete. otherwise you will be on your knees all day using a hammer drill type with flat blade. done it several ways and -- my vote is ... rent. :2cents: