2 months ago - Blitzkrieg Wulf - Direct link
To my experience playing through the Soviet/Russian tree, I would vote for the MiG-15.

If you are a completionist and wanted to spade the Il-28 while working towards the Su-25, then I would pursue that while you have the research bonus. Otherwise, use the MiG. Most of my matches at that BR are determined by which team runs out of players first, not which team can ground-pound their way to victory first.