I posted this in your thread in case you didn't see it...
Pretty much looking at a difference in the taper of the rod. The MBR or Mag Bass Rods have what some what call a versatile taper meaning they are not so much a one trick pony. You can fish a variety of baits on them like spinnerbaits, chatterbaits, swimjigs, texas rigs, jigs, small paddle tails, decent sized jerkbaits, and smaller cranks and lipless baits. I like to think of them as great all purpose rods for folks that can only bring a few rods fishing with them and need them to be able to fish a wide variety of baits. In the Loomis MBR series there is also a 842 and 844. Let the rod model you select be dictated by the weight of the baits your throw and cover you fish.
Your 853 is from the jig and worm series. Meaning it is pretty much a "feel" presentation rod so bottom contact baits and weightless plastics. You may find other uses for it but Loomis was thinking more jigs, texas rigs, weightless plastics, shakey heads, etc.
I have and 842 and 843 from MHX Hi Mod (these were custom builds but the blanks are very similar to the old Loomis blanks) and a current MBR 844 GLX. I use them for so many different apps it is hard to list. What I can tell you for sure is that I am not a fan of any of the MBR rods for frog fishing, Carolina rigs, or larger jigs fished really deep. Outside of that you can really use them for wide variety of presentations vs a rod from the Jig and Worm series.
Like with any other rod your mileage may vary and others experiences may vary.