I’ve had the software since it cost several hundred dollars, back before Google bought it for the proprietary information, and made it free, then orphaned it.
If you have the free copy, best advice would be to go to the dXo site and do a deep dive into information there and see what has been added relative to the original version you have.
The first upgrade they did wasn’t much, but the next two, including the recent one have made some worthwhile improvements with regard to many new presets, and, seems to me, speed. The noise reduction component seems better as well, and to me now seems better than NR in Photoshop, though I could be wrong about that. (I used it, and compared it with the NR in PS a few times last week, which was the basis for my opinion. Previously, I didn’t think the NR in Nik Efex was anything special. It later occurred to me that DXO’s Prime noise reduction is considered by many to be the best in the business, so maybe they ported that over to the noise reduction app in the newest version of Nik Suite. I have no idea, but the new version now seems very nice to me, where it didn’t before. Though this is very much a seat of the pants assessment.)
However, you cannot beat “free”, which is what you have, so “worthwhile” improvements is a personal opinion. Current pricing is still less than the original company was charging for the lesser version of the software suite years ago, IIRC.
I just upgraded to the recently enhanced version, and no regrets, but YMMV, as always.