Is this GSM shield any good?

I was thinking of getting a GSM shield for making a home security system with arduino. GSM modules (not shields) seem to be avaialbe for around 26$ in India ( But they are too big.

I finally found a shield in India for 50$.

The schematic is available here

I want to know what features it is missing. I noticed that it was missing a backup battery option for RTC which is a really big con.