Pensions, in general, are a complex area, even for the most seasoned of financial adviser. SIPPs are no exception, however they offer flexibility and wider choice of investments over and above other pensions whilst maintaining control firmly in the hands of the client and their adviser. At the same time they still benefit from the same tax advantages as any other pension.
With transparent fee schedules often based on flat rates there can also be significant cost advantages to a SIPP for individuals with larger funds and those that take an interest in actively managing the assets in their fund. However there are often transaction charges payable to the SIPP provider for each investment transaction depending on how the transactions are carried out.