Let me start the answer with a quick explanation of Equity SIP and cash segment.

Equity SIP is also called as a systematic investment plan. Equity SIP is called systematic because most of the elements in this investment are pre-defined. The investment tenure, SIP amount, the quantity of shares in a disciplined manner.
Cash segment demands your attention, all the time in the market. Here you need to time the market to gain.

In Equity SIP you can invest through the flexible intervals without the worrying about the right time in the market. If compared both, Equity SIP holds the nature of averaging principle wherein, investor benefits through the low average cost of acquisition of shares. I would favour equity SIP more as it do not demand your close track in market all the time. Also, it helps distributing your investment over a period of time.
If you are aware of mutual fund SIP the mechanism of investment goes in a similar way.
For instance; you may register an ESIP to buy 40 shares of HDFC every month. If you plan to buy shares of 20 companies each month, you must register all these shares under ESIP.

ESIP gives the investor a way to enter and invest in the market even if he is not connected to the markets on a regular basis. I won't be able to recommend ESIP as the best investment as one wrong stock pick up won't help you to make money. However, if you are a good stock picker and believe in long term investment at regular intervals, then ESIP can serve your goals right.