I’m interested to know from anybody who has fished both the differences in techniques, rod power & action. I’m not worried about the weight and sensitivity aspects. 
 

I have the adrena which is quite versatile but am considering trading one out for the other.

I have not handled the Adrena but I have the NRX 873. I have used it for jigs, spinnerbaits, and Texas rigged soft plastic. As far as power and taper goes, the 873 sort of falls between the 854 JWR and the 843 MBR. It's almost a heavy in Loomis stuff but not quite. 

 

It's a toss up for me to chose between the 873 and the 904 for jigs. Both are great and versatile but I tend to like the 904 a little better.

@Bandersnatch not exactly related, but to me the 6'11M+ and the 7'2H have the magic in the adrena line.  From what I know about the 873, I would expect the 7'2H to be a slightly lighter version.  

 

scott

I own the +873 fished the MH along with the M+. 
 

The 873 is much closer to the MBR tapers with a good tip. In my hand it was more powerful and just a bit faster than the adrenas. The Adrena is Shimano mod-fast. If you’ve fished a Zodias, expride, or Curado they are the same taper. 
 

At the price of both in my mind they are bottom contact. I never threw a moving bait on either of them as I have rods which are better at those roles. I stuck to 1/4 to 1/2 jigs and trigs in grass. 
 

If you want to really get a do it all stick pick up the P5 Javelin when it hits. The OG is my favorite stick hands down out of everything I’ve owned. A absolutely true jack of all trades.