MC works pretty well as a PVR. It replaced my Topfield PVVR nicely. Not perfect yet, but getting there.
There are five priority levels you can assign to any recording, including a Series Subscription. You need to use the Standard View to see and edit them though, along with all the other recording rule settings.
After subscribing to a series via the Guide, switch to "Standard View" (Ctrl+1) , go to "Drives & Devices", "Television", "Recording Rules", click on the rule for the series subscription you just created, click on "Configure Recording". Select "Subscription Options" if it isn't already selected, and move through the dialogue windows by clicking next. The third windows has the Recording Options, including the Priority and recording retention rules (Cleanup Mode).
I use the MC jts and jtv recording format. I found a good write-up somewhere comparing the two and decided not to use the ts format, at least initially. I should review that again because there are advantages to the ts format, but from memory the jts and jtv formats give you more capability when it comes to Time Shifting, and in particular saving a whole program from the time shifting buffer, well after the program has started.
I can't find that write-up quickly right now, but if you search the Wiki and Forums I'm sure you will find it.