I have to disagree. The "FREE" access is the same abysmal stuff it's been for years.
The new NFPA Link feature is spiffy, but it's not free (after your first couple of weeks).
NFPA Link is $9.99 a month (though if you bought the abysmal previous digital product, you get converted over for no additional charge).
NFPA link, the previous product (and even the NEC-only PDF, as opposed to the no longer available handbook), it has a full index. The performance is pretty spritely (the old online service was terrible). The search works well. I'm not particularly fond of the way they handle the tables as scrolling things with popouts, but it's usable. Every reference to a different section is a hyperlink.
I'd still rather have bought a PDF of the handbook as I have for the past several versions. They do have the past four versions of the standard in NFPA link and the changes between them are marked. If you need to go back to the older versions there's still the minimalist free version.