I have had them both, for me the minimed is the best hands down.
I switched from a 722 to a 523 Medtronic pump a few weeks ago and notice that it seems to pump faster? I'm not sure if it's the smaller "barrel" or is an optical illusion but the numbers seem to go faster? I haven't tried the Animas one though.
From what I was told by my endo, the slower rate of delivery results in better absorption. And this in turn can result in less insulin being needed. Personally, I love my Minimed pump. I think they are just better pumps overall. But that is my personal opinion and I know many folks love their Pings. To some degree it is personal preference. But that said, if I was going to recommend a pump to someone else, it would definitely be Minimed.
I'm switching to a pump in the next few weeks or so and I've come across this dilemma as well. I currently take about 80 units a day (40 lantus and about 40 apidra on average). I know the ping has a 200 unit reservoir while the paradigm has a 300 unit reservoir. But the biggest selling factor for me honestly is the meter/remote control the ping provides. I'd love to be able to "dial a dose" without having to interface with the meter itself ( I can't seem to find any information on whether the paradigm has a remote or not.).