Another point in SIP is you can never be able to take out all the money that u have put in SIP at once.
For exampl : If I invest 5000 every month from Jan to Dec 2005. I can only take out 5000 in Jan 2006 without exit load.
This is never informed to the investor.Sometimes it is better to invest lumpsum amount at one go whenever the market is down.
SIP only makes sense in ELSS because money is locked for 3 years and hence lump sum dosent really make sense and we get tax rebate as well. For other means SIP is not so good idea. I started Fidelity SIP and since the IPO it is only going up so am not really making any money.I would have been in profit had I put more amount at one shot at the time of IPO. So I personally believe one should keep investing in SIP for ELSS and rest of the amount should put when the market is down or relatively down.