Can anyone give me any information on Tamron lenses?? I found a set including the TAMRON 28-80 VP# AF77M700 and the TAMRON 75-300 VP# AF276M700 plus a camera bag (don't really need one, but, it comes with it) for 300.00. Is this a pretty reasonable price??? Thinking about replacing some old Sigma lenses with them for the new Maxxum 7 I am purchasing. Thanks!!!