canon 55-250 vs sigma 70-300 apo

[parkkibum]

hey guys, i have xsi(450d)
and i'm debating if i should buy 55-250is or 70-300
i did some research and it seems like most people said that IS is MUST for zoom lens. I'll use it to take some landscape and portrait shots.
here's my question
1. will 50mm make much difference in zoom? i read that it's only few steps.
2. macro in sigma apo was kinda appealing to me but how good is it, and is it worth it that i should get it over IS?
3. this is kinda random but would i be able to take shots of moon with either one of those 2 lenses?
pricewise its about same because i saw NEW canon lens for $190 still in box in craigslist and sigma is $209 in amazon. although canon doesn't come with hood nor cap. but they are pretty cheap if i get them in ebay.

[DCBarner]

Bump.

This is my exact question as well.

Dane

[Zion21]

Definitely go with the Canon 55-250. The image stabilizer makes all the difference and its canon quality. I have heard a lot of off brand lens have quality control problems.