How much does knife thickness matter?
Extra thickness can be useful, but it can be quite annoying too.  We have some real knife experts here who will probably go into more detail, but as a kitchen amateur (using the sort of grade knife you're looking at) I tend to use a thinner knife for most things.  Much of what you use a knife for is slicing, and a thick knife adds nothing there. It can even mean that slices break or fall away before you're ready.

A thick, heavy knife is useful for various  things, like fine chopping at one extreme, or getting through a butternut squash at the other, but I wouldn't want to only have thick knives (my thickest knives are tucked away in the second knife block).