Everybody has their own preference for a furler and after reading multitudes of threads regarding this very topic (which furler to buy), I've never been able to determine any that are a clear favorite among the multitude of sources that are all credible. Therefore, you will probably just have to select the one that your gut tells you. It's sort of like that compass that Captain Sparrow uses to determine his course - it always points in the direction that he most desires. I can tell you that between Furlex and Harken, you probably can't go wrong if you are sourcing from SBO, which is an excellent source BTW. Since Ward and I are across the dock from each other, I'll note that his Furlex has a closed spool, while my Harken MK IV has an open spool. Otherwise, I doubt that I could distinguish any significant difference one over the other.
I have found that I sometimes have a problem getting my entire sail un-furled until I go up front and manually pull it out. That may be because I have put too much halyard tension on it. I did use the winch to snug it up. Hopefully, I haven't caused any damage and thinking about it just now, I think I will release some tension next time I'm out to see if there is a difference. I also use my backstay adjustment frequently to increase shroud tension when the wind gets strong and I wonder how that affects operation.