Actually, radiance is pretty awesome item for alchemyst. In higher level play, especially melee heroes struggle with actually getting some damage output, since the have to move in close range to attack and there's a lot of disabling skills involved.. Radiance allows you soak up the disables (presuming that you can live through them) while getting some damage output out..
Also, playing with friends vs public is sure NOT the way to test anything in dota..