Keep in mind that the issue of mirror quality as expressed by Mental4Astro are subjective at best in visual use by a well trained visual observer, however, it is less important in imaging. In imaging you are after presentation of the field to the camera sensor, as a fully(100%) illuminated field. I recently ran a thread that discussed the importance of mirror quality in imaging scopes ( as a precursor to my 10" scope build and mirror choice); the consensus among experienced imagers was that the investment in say a Zambuto mirror was wasted money in an imaging scope, in fact the 1/12 wave finish of the GSO mirror was more than adequate for imaging. There is no doubt that coating reflectivity is higher in the expensive mirrors but this is simply equated in the field by a slightly longer exposure to get the same light ( and I'm talking just a few seconds difference). If your objective is to use the 8" newt where it works best - wide-field DSO photography then the GSO mirror is more than adequate. If you plan on using a DSLR, and are thus constrained by the sensor and pixel size available in those cameras, then the GSO mirror will be fine. There are plenty of very good astrophotograhers on IIS using the GSO truss tube RC scopes, which use the same quality mirror making technology as the 8" newt. Have a look at posted images from GSO scopes and don't be swayed by visual proponent arguments that can be irrelevant to imagers.
Have a read through the thread linked below on imaging mirror quality, paying attention to Clive Milne's comments:
"At typical focal ratios, the focal plane is sufficiently under sampled by any ccd that you are likely to encounter that there is no noticeable improvement to be gained by a mirror more accurate than 1/3 wave.
GSO mirrors are typically much better than that so are as good as you need...... "
http://www.iceinspace.com.au/forum/s...imaging+mirror
Of course, like most threads about mirrors, the usual suspects appear to offer their pronouncements, but even Satchmo has to concede there was little to be gained.