I love Vanessa, but i dont think she can conquer the charts, top 10 would be where i see Nessa, if anything. J-Lo will probably enter the Top 10 [for a short time]. But J-Lo has many old fans, where as loads of people barely know Vanessa, so she has oppurnity to build her fanbase.
With J-Lo they decided if they like her or not by the 1st album, Vanessa has only had 1 hit, and no one knows her at my school. So maybe Vanessa could have a good chance, with more fans coming on.