I personally wouldn't buy any instrument online as you may like the sound of one istrument over the sound of another.. regardless of how good the instrument is.. but if you do not have any music stores around i guess you might not have a choice.
Those instruments look pretty decent, but its really hard to tell how the quality is without seeing and playing them in person. Some things to look for in a quality instrument is flaming on the back/all of the instrument (the "stripes" and whatnot), some grain on the wood, a one piece back (though a 2 piece back is not bad either)
I have an Andreas Eastman vL305 and I love it. I bought it for about $1,500 (new about 2-3 years ago) but Ive seen them online for around $1000
http://www.eastmanstrings.com/eastmanstrings/violins/andreaseastman.htm
I have the model thats the 2nd one down.
http://www.giannaviolins.com/vl/es/esvltable.html
They have one listed for $940
And as a side note, used violins SHOULD go UP in value as they are played and as it ages.
Hope that helped some