Upgrade vb6 to .net? which one to install?

I am going to upgrade from vb6 to vb.net. I was using vb6 for years till now. But due to some limitations i have to upgrade to vb.net.

can any one please advice me which one should i install vb2008 or vb2013? which on is best to use?

for now, only issue that cause me upgrade to vb.net is unicode support as vb6 don't support unicode :(

thanks in advance

best regards