kwahl:
If you want a really first class PHD that you can leave to your kids and will still be digging 50 years from now, I highly recommend the Danuser. I purchased one at auction, opened it to replace seals and the gears, indeed the whole thing, is very, very solid. I visited their factory to pick up the kit, and they are still making them that way. The same family has been running it for going on 100 years (though only making PHD since WW II). Everything is made in US. They make several sizes including a smaller one. The company is similar to the many older, smaller manufacturers that used to dot the US who try to put out the best quality product possible. They are really nice people.
Re Cowboydoc's suggestion for a pounder is very good one. In addition, and not mentioned, is that you can add cutters/breakers and use it to bust up concrete (at least you can on Danuser's models) which you may not need now, but it could come in handy in future projects. I would have bought the pounder myself, but since I already had the PHD (total cost about $800 for an F series PHD - new about $1,500) couldn't justify it.
If you take pride in owning something that is "best in class" look into the Danuser. Also, at least around here, resale on Danuser is good because of their quality so your actual cost (net of depreciation) is less than implied by their actual price.
Regarding down pressure kits, my understanding (from people who have sold them) is they are not as good as cracked up to be because of the leverage when the cylinder mounted on the PHD boom - perhaps some on this site who have used them could confirm or not. I had down pressure or float on the 3pt on an old Farmall and when I went to use it on the new tractor really missed it. You might find it as worthwhile to look into adding a cyclinder to the 3pt to get the same effect with much better leverage (In addition to keeping the auger points really sharpened up and using the "aggressive" tips).
JEH
