Granted, I have never used the 70-300mm DO but ...I was very happy w/ my 55-250mm when I very first started out not too long ago. Now, using the lenses I currently have could I go back and be just as happy with the 55-250mm? Ah...no. I would constantly notice it's shortcomings andit would be even more obvious to me. With that in mind, after you have grown accustomed to using the awesome lenses you have, I don't think you would be happy with the shortcomings that I read about in Bryan's review of this lens. I think they would be more evident to you than to the average "John" using it. You should definitely try it out before purchasing to see if you can accept the tradeoff you are going for. Personally, the "halo" effect caused by the DO elements also mentioned in the review would annoy me.

I say go with the macro lite or wait to see what Canon comes out with in a few months, you won't be missing any shots in the meantime. Being the good friend that I am, you can always dump a lens or two on me to help take the load off! I won't mind! []

Denise