(Typo in the permalink: should be W vs. X. Fixing it will break all the auto-linkies. Hate it when that happens.)
When our lass first began using calculators, I put a pair of Sharp EL-531W calculators in harm’s way around the shop, where they still reside. The new EL-531X seems to have an identical key layout and internal logic (*), as well as the same under-ten-buck price, but I don’t like it nearly as much:
It’s maybe 10 mm wider and doesn’t fit readily in my hand. I’m sure the rounded-rectangle stylin’ mimics a phone, but the cheapnified keys look ugly (particularly the ones around the arrow keys at the top) and don’t feel nearly as good.
The new one fills a gap next to the lathe, where it should collect plenty of swarf.
(*) Including engineering notation with multiple-of-three exponents, which I regard as vital.