If you feel you business will benefit from being VAT registered, you can still register before reaching the threshold (even the 1st day of trading). If you are offering Business to Business this can be a real benefit, in fact it is essential if you want to be competitive/make money.
Also you get the VAT customers pay sitting in your account earning interest for up to 3 months
If you are dealing with end users or small traders who are not VAT registered it may not be worth it and may make your overall prices uncompetitive.
It's swings and roundabouts.