Difficult hunting for that which you are not 100% sure you are willing or able to fork out your hard earned $ for. I have wasted a lot of money over many years buying what I could afford, rather than what I wanted. That said, I finally settled on the 80-400. Used, I see the USA price is ±$800. As for the 28-300 f/3.5-5.6 , see Ken Rockwell ~ he did an evaluation on it long ago , and if the lens had legs, it would have won the 100m in its class. I used a 28-200 kit lens for years and it performed incredibly well. I also used the 70-200 f/2.8 with and without the 1.4 and 2X TC's. At the end of the day, it boils down to only one thing - what do you shoot, what do you want to shoot and how often do you shoot it? How do you carry it, what do you carry with it, etc. A two body set-up is normally the minimum you should look at, if you could. You have great camera gadgets in the USA like the spider belt buckle that lets you clip on a body while the other is in your hand; alos magig shoulder straps etc. I always use it when walking around, for the very reason that you require both WA and telephoto at the same time on such walks. This is a totally subjective opinion, based om what I shoot and how I shoot.
