I have checked several ads and clubs but yet to find one I like. We have just gotten into the telescope thing in the last year and my son really enjoys it. I would like to find and have another here when his class does come out. They concluded that Orion had the best. I got an 8 inch Orion three months ago and then and Orion 10 inch dob a month ago, because I wanted to do more deep sky stuff.
Larger ones are better for galaxies and nebulae and clusters.
Be aware that the bigger dobs can be quite bulky to transport and carry. My 10 inch tube weighs around 35 pounds and is quite unwieldy to carry. And hard to transport in a car, but doable. I have checked several ads and clubs but yet to find one I like. We have just gotten into the telescope thing in the last year and my son really enjoys it.