I've been wondering about them, are they cost effective for someone who prints very little?
In my own case, YES, though I hasten to add that my Laser (a Brother actually, though I think it makes little difference, any of the big names seem more or less the same) is "only" B&W printer. At a very rough guess, since retirement I probably print no more than about 30 to 50 pages per month.
I probably use one toner pack about every 2 years, perhaps a little longer, and at about 20 quid (equivalent) I find that not too bad. One "trick" (which was listed by Brother in their Manual BTW) is when you first notice your prints getting a little faint, remove the toner cartridge and shake it side to side a bit (not too violently), then replace. That seems to help, along with setting the printer to "toner saving" for all prints. That doesn't seem to make the prints at all faint.
BTW, I always have a spare toner cartridge on hand, and it stays within its sealed plastic pouch (and cardboard box) until its actually needed.
However I do also have an Epson colour ink jet printer, simply for photo printing these days. Again I don't print all that much, but at the time I bought it, it came up with good marks in all the reviews for high quality photos (with the special Epson paper, which I also use). I print perhaps <10 photos per month, on average. The specific model I have is the Epson Stylus Photo R360, but as said, it's probably at least 8 years old now, maybe more. The cartridges do dry out from time to time, though I keep the printer covered when not in use, and it's also half way up the wall on a shelf, and not directly in front of a window, all of which MAY help delay drying out. Although the cartridges are VERY expensive (IMO) at least the R360 has 6 separate ink cartridges and it will allow you to change them individually so buying "1 or 2 at a time" is not too pocket busting.
I did try non-Epson cartridges once, but despite the manufacturer's instructions, I never did manage to get the Epson to play ball with them. But at least I did get a refund for those when I returned them.
HTH