There are a few things that lead me to buying a Harken MK-IV last year.
For me the choice was very easy as I was able to see them side by side and all the Parts and pieces. Pro-Furl is a very well built unit as are Schafer & Furlex but at the time I was buying Pro-Furl had been sold by the founder and parts were hard for my rigger to get. This piece of info alone made the Harken a very easy choice. I know Harken to be one of the best in the business for customer support and they will be there when you need them.
I chose the MK-IV over the less expensive cruising model..
#1 The MK-IV has four more races of Torlon bearings than does the Cruising model and neither ever need need any lubrication.
#2 The MK-IV has unique independent upper & lower swivels the Pro-Furl does not. These swivels allow the head and tack to lag behind foil as you pull on the furling line. This feature allows the center of the sail to furl first and the tack and clew lag behind because they independantly swivel on their own. While many furlers have an independant top swivel only the Harken has both top and bottom swivels that are independant for a much better reefed shape. With two extra rows of Torlon bearings in both the upper and lower drums, that support this feature, the sails furl easily even under load not that I suggest this. That indpendant swivels help aid in a better sail shape when reefed and it WORKS! This feature is worth EVERY penny!!
#3 The adjustment factor is a BIG plus! Simply pull a pin and loosen four allen head machine screws and raise the drum to have access to the head stay turnbuckle. See photos..
This is how user friendly the
Harken MK-IV really is:
Step one: Loosen these four bolts and pop the retainer plate out off the corresponding notch on the foil (you do not need to take them all the way out, just loose, a NICE feature to prevent losing the bolts):
Step two: Remove this pin and slide the drum up the foil and snug down the previous four screws to hold the drum up and out of the way:
Step 3: Adjust your turnbuckle! Yes it's that easy!!!