My GS Dob, 10” works very well now. Yes it had a few issues re mirror clamp to tight but over all it was good.
I have flocked the tube which I think has helped. Collimation is very important.
But most of all seeing has the most effect on Planetary views with collimation.
I use to have a 6” Achromat and my 10” is better than that. Eyepieces make a big difference also. Cheapo EP’s are no good. Stick with good quality EP’s and a good Barlow and when conditions as in seeing are on your side you will get nice planetary views.
Cheers.
