Personally, I think the pacts are too big, and for something so versatile, miss key features like volume control, backlit LCD, etc.
IMO the one that does it REALLY right for someone looking to practice is the CED8000. Has headphones for peaceful; at home par-time dryfire. Has nice LARGE numbers that are also backlit, and the menues are easier to deal with IMO than the 20 buttons on the back of the pact. That's what I own.
However, that being said the CED7000 is uber convenient, but doesn't have the headphones like the 8000. It does have a low volume mode. One of the guys I shoot with has the 7000, it's really small and convenient. You can actually strap it to your forearm without issue. It's also rechragable, which is nice given the price of 9 volt batteries.
The pact IV and club are both larger than they need to be.