I've been fishing the NRX 893c 7'5, m/h, ext fast and NRX 854c 7'1, Hvy, Fast for over a year.
I also fished/owned the MBR843 in both IMX/GLX models and the GLX MBR844.
The sensitivity between the GLX and IMX is noticable, but I have very sensitive hands. I preferred the MBR843 over the MBR844 because I think the m/h was a bit more versital over the hvy. If I had to choose between the two and was fishing ONLY T-rig worms and jigs 1/2+ with 14-17 pound mono then I would get the MBR844. If you only had one rod for fishing lighter jigs up to 3/8oz, T-rig worms, fluke style baits, jerkbaits, occasional crank bait and using 10-12 pound mono then I would go with the MBR843.
I sold all my IMX and GLX's and upgraded to the NRX's, except for my crankbait rods.
The NRX's are definately more sensitive, lighter and supposedly stronger than the GLX, but may not be worth the extra money for many anglers.
My suggestion is this. If you can afford it then buy the NRX for all T-rig worms and without a doubt Senkos (especially weightless Senkos) if fishing open water to light cover/grass. The sensitivity you get while using weightless Senkos is unimaginable. I use the NRX 893c exclusively for my Senkos.
I use the NRX 854c for T-rig worms and jigs up 1/2oz. My biggest dislikes about the 854 is that it's only 7'1 and I'd like to have a longer handle. I would NOT use this rod for POWER fishing. By Power fishing I mean flipping heavy pads, weeds and junk with #80 braid and 1/2 - 1.5 oz flipping weights and swinging 5+ pound bass into the boat. Jig fishing around docks is no problem with this rod but not enough for pulling bass through 10' of thick hyacinth(sp).
I look at NRX rods as being used for "heavy finesse" fishing.
I'm losing my train of thought and keep dozing off so I'm signing off for now. Can add to this laster if you'd like. (LMAO, I just did a big head jerk and nearly flipped myself out of the chair)