To be honest I've had one or two ok communication experiences with Indian call centres and I've had a couple of experiences with UK call centres when conversing with folk with strong Irish and Scottish brogue has made the situation more complex for communication.
On the whole though I've had better communication with UK centres than the overseas ones.It's got nothing to do with technical expertise just an inability to hear clearly what someone is saying to me in heavy accent British or Indian.
Technically however they have been brilliant.