Comment 29 for bug 170378

> ScislaC suggested we could go with another submenu like "Select Similar"
> instead of "Select Same" with tolerance values stored somewhere.

That would be really useful, I see a nice application of this feature: you could select all widths inside a given tolerance, then apply exactly the same width in the "Fill and Stroke" dialog. So selecting "similar" objects should not be the default, but be used only to "clean" messed up designs.
You can't take full advantages of such a selection mechanism if the styles are not well specified.
Personally, I pay a lot of attention to applying exactly the same style to objects that must share it, so rounding problems don't affect me. Of course, if you create an object with a 2 mm stroke width and then rescale it to 50% (having the "rescale stroke" option active), you could not get exactly the same stroke of an object created with a 1 mm stroke width, and I feel this is reasonable because the operations done are not adequate for getting a precise drawing. But this even worse with colors: it's almost impossible to apply exactly the same color to two objects after manipulating the two: you have either to copy one to the other or use the palette or numeric input.
So, to me the "similar" approach is an useful option for correcting messy drawings, but I'd vote for the stricter "exactly the same" approach for the default behavior (and this could be achieved setting to 0.0 the tolerance parameter, so each user could specify what needed).