After using lots of cheap rt data service like MDP, Manshi, Databull etc., I found one common problem with them. They have all missed ticks. I've several trades, but those price were not on chart. Also updation was gradually becomes slow. Before using these data providers, I used IRIS as well as Spider software for quite sometimes. At that time I never faced such type of problem. But due to their cost and due to my preference (only USDINR) of trading, later I switched to those data service. They never accepted their fault but always said the fault was lying from my side.
Finally I switched to NeoTrade Analytics. Surprisingly the data was ultrafast and the updation was as fast as NEST terminal. There is no missing ticks and their service was very good. Yesterday (Tuesday), I find an issue i.e. although USDINR 1M made a low of 60.25, my chart recorded a low of 60.2525. When I contacted them, although they can not rectify it till now but they are so serious on that matter I can not explain it. They contacted me several times on this issue by phone and told me they have reported this matter to NSE. Still I am very much satisfied by their effort and service.
I am subscribing to their currency RT data service for 3708/- (including service tax) for six months.
Hope, this information will help you all.