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Phil
Star images with low power combined with lots of light , will look worse as they use a larger part of your pupil and they show up the inhomogenities in the cornea of your eye. I find it takes a 2 to 3 mm exit pupil before my eye aberrations aren't affecting the brighter star images.
You don't mention
a) whether your scope was fully acclimatised to give its sharpest possible images.. this can take up to a few hours.
B) whether you actually had steady enough skies to allow an 8" telescope to reach its theoretical perfection .
C) Are your star images at a defocus position showing say 10 rings looking symmetrical and even both sides of focus ( indicating good collimation and state of equilibration ) . This test needs to be done regardless of what your laser might tell you about the state of collimation. A star test is the `acid' test as it were.
Those issues need to be ticked before you can make any serious judgements about optical quality .
If you don't have the time to get to know your instrument in this way then an 80mm ED refractor is a good choice..little in the way of thermal issues and images will always look superficially sharp as the aperture does not have the resolving power to be affected much by local `seeing'.
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