NCSkibum-
I'm new here, but not new to diesels. I recently traded a 2014 F350 SRW 3.55 for a 2015 F350 DRW 3.73.... essentially identical trucks (ultimate Lariat, etc.). I do like the truck better as a tow vehicle. Frankly, I can't really discern a lot of difference in the engine... maybe more punch mid-upper end. I can, however, tell quite a difference between the 3.55 and 3.73 and the DRW. I also like the exhaust brake compared to the 2014. Having towed my cyclone 4100 with both, I would say you should definitely consider the 2015. The 4100 felt like it was too much for my 2014. The 2015 feels "just right". At least that's what I told my wife!!!! I'm happy to answer any other questions you might have. I see you are in NC; I'd be happy to hook up the 4100 and let you experience 1st hand.
Good luck,
Jay