I donīt know anything about the Blackhawk press. But the big difference between it and the Dayton press is that is uses a manual pump connected with a hose to a cylinder, instead of just a jack like on the Dayton press. The shop press we have is of the Blackhawk-style, and it uses two different pumps. One big volume/low pressure and one small volume/high pressure. That makes for a faster operation, but there are also more parts that can fail. If you are only going to use it once in a while and donīt want to put too much money into it (when buying a new one) you should choose the Dayton type. If it fails you can just switch out the jack for a new one.
On the other hand, if you believe you will be using it every week you might want the Blackhawk type of press. At least if it is equipped with the two pumps as described before.
I guess when buying a used press itīs all a matter of what you stumble across. The important thing is to make a good deal. So if you donīt like it you can always sell it without losing money.
