@Vikas When I say most of the lenses are higher quality I mean most of the lenses are higher quality.

@Vikas There are some less than ideal EF lenses (EF 75-300mm f/4-5.6 II is probably the lowest quality lens in Canon's catalog - it's also one of the cheapest as Canon or authorized Canon dealers practically give them away in two-lens kits with a new low end body) and some higher quality EF-S lenses (EF-S 17-55mm f/2.8 IS), but by and large the EF-S lenses are lower optical quality than EF lenses in the same focal length and maximum aperture range.

This is especially the case with Canon's "L" series of lenses.

@Vikas When one uses an EF lens on a crop sensor body, you get the middle 40% or so of the picture you would get with the same EF lens on a FF body. If you then display it at the same size, you're magnifying it by about 2.55X as much, so you will be able to see defects more easily. But you're also magnifying the image by the same amount when using an EF-S lens, so you'll see defects just as easily with EF-S lenses when using a crop sensor.

When using a FF sensor with EF lenses, you're only magnifying 0.4X as much to get to the same display size, so the defects are magnified less and thus less easy to see.

@scottbb You don't spend much time on photography pages such as DP Review and Canon Rumors or Nikon Rumors, do you? Those folks see a need to change gear anytime any new product is rumored, much less actually introduced!