Yes I have the same issue with my brand new Lenovo P780. Actually more than 1 problems:
1. Network keeps cutting off .. however at the same location with the same network provider (Vodafone and MTNL - Mumbai) and same SIM card when inserted in my Gionee G1 GPAD the network is awesome and 3G network is constant. With the P780 the 3G keeps switching to EDGE and back, also I get just 2 bars of network when indoors. The connection constantly times out and the downloads break.
2. Sound of caller is very low, this is not a network service provider related issue as this happens with all service providers. I have tried with Reliance GSM, Airtel, Vodafone, MTNL and IDEA. The have actually guess what the caller said. When connected to my bluetooth handsfree the sound clarity is superb and audible.
3. The PUSH notifications do not work however in my case this is awesome else I was getting some crazy notifications from my service provide inspite of having activated FULL DND ..
4. While in the Video Player (default) of the phone on clicking on "Brightness" I am unable to slide the notch upwards. It takes several failed attempts to increase the brightness however my MX Player Pro works awesome in this case. But I can live with it.
5. The Lenovo Power Saver sux royally, there is no way to program it to open the connection in intervals to receive emails and whatsapp messages. Either it is a Full cut or a Full open connection. I prefer to use the 2x Battery saver (paid version) instead with intervals to start the 3G service every 5-10 mins to get work done.
Otherwise this phone is the best in the market so far. I have owned Samsungs (Galaxy Y and ACE), Karbonns (A9+ and A1), Micromax (A110 and A116 HD), Videocon (A20 and A30), Gionee G1 GPAD (present other phone) and also have a Galaxy Grand (which my father now uses).
The lenovo beats them all hollow if I do not consider the above problems.
Can someone at Lenovo please help me ?? I have contacted the Lenovo tech support helpline and they guided me to the HCL service center in Mumbai saying that I will get a DOA from them and then I have to give it to my dealer who will replace the phone. But its a pity that I am unable to use this fantastic phone.