So what is the latest on the one spouse taking early/one delaying strategy?

The Kitces article I linked to above explains it (I linked it below as well). But essentially, the issue is longevity risk. In a nutshell, the strategy is for the higher-earning spouse to delay, but to for the lower-earning spouse to claim early. If the higher income spouse dies first, the lower income spouse can claim the higher survivor's benefit, which likely erases the benefits of lower spouse delaying. So the early/delay strategy makes sense for that reason.

If the lower income spouse dies and claimed early, the higher income spouse already has the higher benefit, plus got the utility of the money from lower income spouse early claim. So the early/delay strategy makes sense for that reason too.

kitces.com - Why it rarely pays for both spouses to delay social security benefits

There is some nuance to it of course. Some good discussion in recent thread on Bogleheads about some of the considerations (such as taking into account Roth conversions). The OP asked how many people were doing the early/delaying strategy and most people responded that they either did or intended to.

https://www.bogleheads.org/forum/viewtopic.php?t=4...