I purchased a karbonn kc750 dual sim (CDMA+GSM) mobile on 28/2/2010. Below is a list of issues I have with this phone.
It was mentioned on the box that the mobile supports Hindi also but only English is supported.
The software is not stable, sometimes I get different menu in SMS i.e. to store the SMS to phone memory but at other times it is different menu which does not allow storing the SIM sms to phone memory.
When I make a call, I get another call from "unknown caller" which is same call I have made and if I take the call nothing happens, if I disconnect that call then my call is disconnected.
the phone suite provided on karbonn mobile website is for 64-bit operating system but not for 32-bit operating system.
When connected to a computer the phone could be used as storage, com port to webcam but webcam feature is not working.
When I change the ring tone in a profile the old ring tone is shown as associated with that sim but the ring tone is changed.
Sometimes changing the rine tone for CDMA or GSM, it says SIM1 only, not SIM2.
The mobile software is very unstabled. They should provide the firmware upgrade free of charge through their service centres and website.
The only things about this phone to make it a buy are
CDMA+GSM
big screen
mp3 as ringtones
value for money
simple design
Now you may decide on your own.