I don't have any experience with a BMW K1200LT seat sent to MCC, but I have a high end multi-layer memory foam MCC seat on my VTX1800. They were fantastic to deal with, fast, detail oriented and definitely great value. My wife loves the seat on the VTX, where she simply hated it before the MCC mods (and the rider seat was even worse - 50 miles and you were looking for the nearest place to pull over). I am super happy with my MCC seat on my VTX, as are hundreds of other VTX owners that I've seen and chatted with on the VTX Owners Association message boards.
I won't attampt to compare the two seats on my rides because it doesn't make sense based on the starting points and shapes being so different between the two bikes. What I do know is that MCC will customize a seat to your height, in-seam, front to rear position etc if they have experience with that particular model bike.
I've often considered modding my K1200LT (day-dreaming really) but it doesn't seem worth it right now when I'm basically OK with what I already have for the riding I do (I believe I have the soft seat on my K1200LT - it's noticably softer than my friends '02s and '03s). Now if I did not like the stock seat on my K1200LT, or was doing longer rides, I wouldn't hesitate to do it with MCC.
That's my 2 cents - hope it helps.