Generally the Bellanca 14-19 is faster for the horsepower than a Downer Cruisemaster. My buddy Russell Williams has a Downer 'Master and said some not nice things about the Bellanca version on his web site but he did so largely to acquire my goat. As I have little need for a goat, I complied. He's been a big help to me these past 30 months getting 6561N back into good condition.
Seriously, they cruise about the same. The Bellanca has a narrower cowl and could be a tad more efficient than the Downer, but the Downer has 40 more horsepower making the climb difference quite different between the two. On a standard day, with two people aboard I'm happy with 1100fpm. I've seen Russell's hit 1800 with a similar load on a cool day.
Also, the Bellanca has a controllable, rather than a constant speed prop. My O435 has been rebuilt as an -A2 meaning that it has higher compression pistons and can produce more horsepower but only at RPM that can get a bit scary, or worse if you fail to pay attention to the tach during climbout.
Both can have autopilots. Mine has a Brittain wing leveler that works wonderfully, plus Brittain also makes add-on modules that allow it to track a VOR or GPS heading. No alt hold, no auto steering (you twist a knob to steer to the new heading). Brittain is still in business and still makes the parts for both models.
Jonathan