The Telegraph published a long and complicated article in which it showed that savers and investors would mostly do better putting money into pensions than ISAs.
For higher rate taxpayers the advantage was large, but there was a worthwhile advantage even for those paying basic rate income tax. This analysis follows the new pension rules that apply from April 2015 and permit people to withdraw money as and when they wish.
The one aspect the Telegraph did not focus on was access to cash. With pensions, the earliest age you can access cash is 55 (but this will rise in future), so there is still an argument for using both the tax shelters. But there is no doubt the financial balance of advantage has shifted from ISAs to pensions, so you may wish to review your current savings and investments.