One of the interesting points about V1 go/no-go situations is that there is NO margin built in to the figures. The climb performance in the various stages of the take-off after an engine failure has a small margin built into it (ie Net performance) which means it is very unlikely that you will not meet the stated performance. There are no such margins in the V1 stop/go part of the equation, you are dealing with gross performance and there is a very real chance that in a runway limiting situation you can do everything right and still end up off the runway.
The prospect of a over run on an limiting runway prompts some people to consider continuing the take-off even if they are slightly below V1. This also has huge risks depending on your location. On a take-off that is not field limited there is a spread of possible V1 speeds that fall between the min. and max. V1. The Max V1 is a speed after which you cannot stop in the remaining lenght, the min V1 is a speed below which there is not enough runway left to accelerate on one engine to VR and get airbourne. One figure is used to keep things simple but on a field limited take-off at max. weight the figures are the same and if you continue the take-off after an engine failure more than a few knots below V1 you are unlikely to be able to achieve VR by the end of the tarmac.
On balance of course it is far better to be go minded but the other side of equation is well worth bearing in mind I think.