Jets use V2+10
JIC,
If you lose an engine during initial climb, you then need to be at V2. You will probably lose a couple of knots as you respond to the failure, so on a normal departure you should climb out slightly faster than V2 (best engine-out speed).
Your climb performance with all engines at V2+5/10 is very close to what you get at V2. The performance loss at V2-5/10 is significantly less, especially if you are engine out.
Hope that helps.
Joe