I have seen hundreds and hundreds of galaxies, Nebulae that fill the lowest power field of view, the shadow of Jupiter's moons cross its cloud bands, the could bands on Saturn, five of Saturn's moons, details on Mars, stunning globular clusters that look like 100,000 stars (which they are)....
Personally, and like many on CN, I think Dobsonians are ideal for most serious beginners who are willing to take a little time to learn how to collimate the telescope and also move the larger telescope.  My first telescope was a 10" Dobsonian and I really don't regret anything about getting one as my first telescope.   I have seen hundreds and hundreds of galaxies, Nebulae that fill the lowest power field of view, the shadow of Jupiter's moons cross its cloud bands, the could bands on Saturn, five of Saturn's moons, details on Mars, stunning globular clusters that look like 100,000 stars (which they are).... My 10" Dobsonian simply blows away the 4.75" refractor and 90mm MCT for the vast majority of objects (They have their purpose though which is why I also own these smaller telescopes).   In general aperture really helps.   If you can find a used 8" or 10" Dobsonian in your price range, it would be my choice.