RKglobal :
you'll get ODIN;
you can trade equity, F&O, currency and commodity.
charts are primitive.
brokerage - 9 per lot + monthly software charge per segment (329/-)
customer service - ok. 2/5 star. you usually don't encounter problem, but if you do - good luck solving it soon.
Zerodha:
you'll get NOW; faster than ODIN
you can trade equity, F&O; commodity and currency not yet started.
charts are not there at all; not even upto ODIN level.
brokerage - 20 per executed order. no other commitment.
customer service - best 4/5 star for prompt response and knowledgeable staff.
given the ambitious pipeline that zerodha has, i'd incline towards them.
RKG has a lot of quality to catch up....!