Speaking as someone who has managed to fly all sorts of random speeds in the sim. following an engine failure, I can tell you for sure that it takes absolutely ages to get your speed above V2 if you let it fall below. Flying at precisely V2 is possible but V2 +5 just a little bit easier, with a buffer built in. But if you fly much faster than V2 +5 (or V2 +10 in my plane), your climb is adversely affected. So V2 +5 is a reasonable compromise.
PM