If I were to invest in a fancy thermometer, it would be the temporal. Actually, I would like to have one on hand, but it just hasn't seemed essential yet.
If I understand correctly (my SIL is a nurse) they use the ear canal ones so much n drs offices, etc. simply because they are quick and easy, and they really aren't that concerned so much with accuracy for just a check-up. Just need a number to write down.....in cases when they are concerned about accuracy (charting the temp changes) they stick with oral or rectal.
I think lots of offices are starting to move to temporal, because they do seem more accurate, and they are still very easy and quick. When my eldest was born 5.5 years ago, he was monitored for jaundice for a few days and the home health nurse they sent out to check him used the temporal type. They weren't yet available to consumers at that time, but he said they were extremely accurate.
Personally, I pretty much never check temps using a thermometer. It doesn't really seem necessary. I know when they are feverish, and it is so unlikely that the temp would spike to an alarming level (above 106) without there being plenty of other symptoms to indicate that I needed to seek medical care. Fevers have a purpose, and I try to let them do their job when the kids are sick.
If I had a child who had other medical issues and more accurate, more frequent monitoring seemed a reasonable thing, that would be different, of course. But just to take a temp to know whether it's "above normal" or not doesn't seem very useful to me. JMTCW....