Newtonian mirror 10" where available?

For those building their own telescopes. What are the best least
expensive sources (stores, shops) of these more than 10" newtonian
mirrors?

I'm deciding whether to get the 9.25" SCT or build a 11" (or
bigger) newtonian mirror.

The latter has less obstruction and more light gathering so it
should be better than SCT but how come so many people
still buy SCTs?

A newtonian has no corrector lens so there should be
some aberrations. Is this why people get SCTs or is
the aberrations easily ignorable?

Thanks.


Teni