All things being equal the darker the sky the larger the telescope the better? most of the time anyway
I saw the companion of Antares easily last night with my 250mm Dob where I struggle to see it with my 300mm. My 120mm refractor just shows the 5th member of the Trapizium while my 300mm Dob shows 6 members with a casual glance and during astronomical twilight. The refractor will show more detail on Jupiter on most nights while my big Dob will show more moons of Saturn. I guess it comes down to experience and observing prefrences with what you will get out out a telescope at a given location.