The free EPG is probably going to be pretty useless for you. It relies on information transmitted with the video on each channel and is A) only a couple hours deep and B) not present for every channel.
The subscription EPG is a lot better. Unfortunately, the EPG software itself is not very usable in my opinion. The user interface is very limited and (in my experience, anyway) it cannot schedule programs back to back without complaining of conflicts and aborting. This is even with zero padding before/after a program.
I finally decided the EPG itself was totally inadequate and tried other PVR applications. The best free one is GB-PVR, but it does not support any tuners that use software encoding (like most of the USB tuners from Pinnacle). The best paid PVR software is BeyondTV, which works perfectly with Pinnacle tuners (hardware or software encoding versions). It is expensive but the purchase price includes perpetual EPG updates. It does have a free 21 day trial if you want to see how it works.
Too bad... the tuner itself works great.
I finally relegated my Pinnacle tuner to live TV only on another PC and bought a PVR-150 for $35 off Ebay. It works great with GB-PVR.
Paul