China Unicom used to operate both GSM and CDMA. But recently China Telecom acquired China Unicom's CDMA business. So there are 3 carriers on the market: China Mobile, China Unicom, and China Telecom. And they all launched 3G services. As a new player, China Telecom offers the best rate in order to expand market share. As for cell phone rental services, just google "cell phone rental China" or "cell phone rental Beijing". There will be a bunch of choices.