I just picked up a conversion kit for my Lee Classic Cast press. These things are great! No more fiddling with die adjustments when I change calibers. I tend to load up 15-20 test loads for 2 or 3 calibers at a time and Hornady has taken a lot of the hassle out of it.
The only thing I see that needs improvement is that the piece that you thread into your press needs to have wrench flats on it. I put a drop of blue loctite on it because Badnews Bob said that his occasionally tries to come loose when he takes a die out.
Another drawback is that my dies won't fit back into their boxes with the bushings on them. I have one set of RCBS dies and they will fit in there, but both the Lee round and flat boxes are too small. I just inverted the lid from the round boxes and set them in there for the moment. I'm looking for some square utility boxes that will fit the bill. RCBS wants over $4 each for their die boxes. I'll check out Midways offerings.
Ian