i got a Sigma Super Macro APO II 70-300mm since last year, not often use it but just can describe it in 1 word, "SUPERB!" (for low budget and noob like me lah muahaha)
erm...its heavy, 500g+-(lens bag included dun woly haha), but it will gv u nice pic xspecially macro pic. I rmb i bring mine to redang,took sum pics and the results was so damn nice(compare to my 28-90 kit lens lah haha)
then for macro, before i get this lens,the method i use is hold a magnifying glass infront of the standard lens,pics okloh...can say lousy quality macro lolx,then after i got Sigma,hua.... my macro pics starts increasing haha
well my noob opinion for u, if u really wanna get a 300mm and ur budget below 1k,then Sigma Super Macro APO II is the right choice,i 4got what name but a mag has make survey on same the categorise lens,and sigma has been chosen as the smart value lens