Anyone have any experience with these? Whats the difference between the deep flex series and the regular cranking series? I'm looking to get a Shallow/Square bill cranking rod and was thinking about picking one of these up. Are they worth the cash or is there better options?

I had a CBR843 for a few months and absolutely hated it.  It was severly underpowered for pretty much any crankbait I threw, an LC RC 1.5 absolutely pushed it to it's boundaries.  It was very whippy and struggled casting heavier baits. 

If you are set on a Loomis, I'd go atleast with a H powered rod, if they make one.   I tried to like the M but the 6'10"MH Carrot Stix Gold i was trying to replace blew it out of the water in all aspects IMO.

I have the CBR843 ad LOVE it, for smaller cranks. I use it with dive depths around 5-6ft. and 1/4 ounce rattle traps. I have it paired with a SOL and #8 Yozuri mono. The combo is very fun to fish and have had no problems bringing 4-7 pound bass.  This is, however, an open water rod.  It does not have the balls to drag decent fish out of the grass or rip traps through the grass.

Now, if you're fishing deep cranks then get the next size up rod. The CBR843 will be too lite. I am currently using my Senko GLX rod 7'5 for deeper cranks until I buy another crank rod. By the way, the Senko rod actually works very well with the cranks.

I think the CBR845 would probably best fit your needs.

they are underpowered for their rating. if you think you want the 843, buy the 845. if you want the 845, buy the 847.

i personally found them to be too sensitive for cranks or something. i loved it at first but then found that my hookup ratio with them was pathetic. i went back to glass rods for cranking and am much happier.

CBR843 is kind of whippy but great in casting 5/8 LC FM110 and lighter lures.  Difficult to control landing a fish weighing more than 4#s. 

cbr845 is the best all-around of the lot, imo...cbr906 for open-water distance...cbr785 for sidearm targets.

I've got the 843 and 847.  The 843 IMHO is great for 1/4 and 1/2 oz traps and small crank baits.  If I were to only have one rod I would go with the 845 though.