Mobster - a point
When you want to compare shots from two different lenses together you have to really do it a certian way.
Firstly webshots are a not a good way to compare lenses, shots are usually around 1/3 of the size they are originally and that will hide up a lot of things such as noise, sharpness problems, lens imperfections and more - its also a lot easier to hide those things on a smaller shot as well. Not saying this is wrong, but that it makes comaring lenses with such shots rather impossible.
Better is to look for 100% crops of shots (That is a crop taken from the fullsized image and then posted to the net - that allows you to be able to see what the quality is like at 100% image size without people having to upload the fullsized image.
In addition its also usefull if the images are taken by the same person - since any errors in shooting will (most likley) be repeated in all their shots - thus you are able to compare like for like images rather than images which might show user error rather than kit failure
Further, unless there are key quality differences between the lenses (ie one performs significantly better than the other) user opinions will be tricky to define which is the better of the two - a trip to a photography shop should be able to help you here - many are willing to get stock in to allow users to try them out and also allow you to take some test shots with the lenses as well (if you take your own camera along you can take the shots home to compare on the computer as well- don't trust your LCD to show you the images. Also, if your testing at a shop try to get some outside shots - indoors lighting is often very poor which can lead to bad images if they are not taken right - outside is generally much brighter and thus easier to get good exposures