Mewlon 300 ($US17000) or C14 ($US3000)?
The price of the Mewlon makes it a non-starter for most of us. A C14 with cooling holes added is an adequate instrument, and will out-perform the Mewlon 250 in brightness and resolution, and probably equal it in contrast. Perfect optics don't necessarily compete against the brute force of larger aperture.
(I'm sure some logical person will mention a Dob soon
)