I was told by our rigger to not buy the cruising model. He was told this by a Harken distributor. Apparently it was designed to meet the requirements as standard equipment to keep costs down on some production boats and the quality of the equipment is nowhere near as good as the standard Harken Mk 4 model. It is radically different from the Mark 4. If you contact Harken I am sure they can explain the differences better. I can't recall them offhand, or I'm blocking out the vacation week where the torque tube broke on the second day of our trip.
The same was told to me by the rigger at our marina, also a Harken dealer and a Harken design consultant.
I can also second the ability for the new Harken unit 2 for maintaining great sail shape when furled. I was experimenting with it a few days ago in 25 knots and was very impressed with the performance/sail shape it was able to maintain, even furled almost to storm jib size!
I asked a similar question a couple of months ago and many made great recommendations for furlers, Profurl, Furlex, Harken, Schafer, all great units, but ultimately, I went with the Harken MKIV
Unit 2 for economics, convenience, and design.
BTW...I had the yard install the unit for me, but I helped and observed so I can hopefully resolve and issues if/when they happen, I hope you can do the same, it was lots of fun to see it go together. If your in the Baltimore area and are interested in the Harken product I can direct you too whom I purchased mine...you wont find a better price!