If
aceman falls under certain classes of British nationality, acquiring OCI status may present complications for upgrading nationality to a full British Citizen. The UK seems to be the only country that treats OCI status as something akin to a citizenship rather than a visa (which is what it is, despite its name). See
Wikipedia.
There are no other negative complications I am aware of. It really is a great convenience for frequent travelers to India as it affords travel to India for most typical purposes (family visits, business, employment, tourism) for any length of time with hardly any restrictions such as any residency requirements. If your ties to India are stronger and you are contemplating moving there the OCI also allows you to move to and reside in India indefinitely without needing to show a job offer or anything like that.
There are no tax implications for short visits. Of course, if you stay in India using the OCI for longer periods of time you may end up triggering tax liabilities for yourself based on the length of stay (more than 182 days in a year, etc.). But that's an effect of the residency rules for the Indian tax authorities, not anything special about the OCI visa.