Hi Derek, welcome to the Cameralabs forums and thanks for your kind comments!
I have changed the title of your post so people can see more easily what it is about and provide their advice. I hope you don't mind!
I haven't tested the three lenses you suggest, so I can't comment on them. I have however tested the Canon 70-300mm IS USM
and while the construction isn't fantastic, the quality is pretty good - and it has Image Stabilisation to combat camera shake.
I also hope to test the Sigma 50-150mm f2.8
soon. It doesn't have stabilisation, but it is optically quick.
But both lenses cost about $550-$650 US, so they're beyond your budget.
Have you considered a second hand lens? You might find a bargain?
But if your budget for a new lens is US $250, then it looks like a cheaper Sigma is probably your best bet. The Sigma 70-300mm APO
is available for about US $200. It's a little bit more expensive than the non-APO version, but the APO models are normally worth having. It's probably your best bet unless you want to go for the stabilised Canon or the faster f2.8 Sigma lens.
Has anyone out there got a 70-300mm for their Canon which they'd care to comment on? Or indeed tried the Sigma telephoto zooms on a different mount?