If the savings is worth it to do the transit, that's your value judgment to make. PEK T3 is not the greatest to transit in, as it's too big and not very passenger-friendly in term of nifty amenities available a la SIN. However, it is easy to find your way around, it is very clean, and it is surviveable. I don't find the staff unfriendly, just the usual Chinese quasi-governmental attitude "I don't give a s**t." Immigration and security back to outbound are reasonably efficient and polite. As you've decided you aren't interested in heading into the city (or maybe don't have long enough), then once you get your transit stamp at the appropriate immigration desk, your choice will be to either head back to and stay on the airside (secure) part of the airport, or stay as long as possible on the arrival (nonsecure) side. The latter has a bit more in the way of restaurants and other stuff. The airside area has the CA lounges (F and Biz/*Gold) assuming you have access.

One more thing: PEK ATC can be maddenlingly conservative with spacing of flight arrivals and departures. If there is any type of weather, including light showers or fog, expect delays, esp getting out on the HKG flight. So if your arrival in HKG is time-sensitive, keep this in mind if you choose a PEK transit vs a direct TPAC to HKG. There are plenty of comments elsewhere about CA ground service and international flight service quality, so I won't comment on that here.