Would appreciate any input on the ride quality of the BMC Pro Machine. One review said "smooth", but I've heard some say "not a good choice if comfort is important". I tend to believe the latter. Thanks in advance for any real life experiences.

There are two things that will have an affect on "ride quality:" wheelbase and fork. A longer wheelbase provides a smoother ride. The Pro Machine has a fairly short wheelbase. So, I'd expect a harsher ride from that alone.

Since the fork is cantilevered off of the frame and is free to move, it can absorb some road shock. Unfortunately, it's difficult to compare forks without actually riding them. The Pro Machine comes with an Easton EC90 fork. In my experience with the original version of that fork, it was a fairly nice ride. Because it is all-carbon, there is no bonding to metal at the crown. In order to ensure that this bond is strong, most makers overbuild it which stiffens the fork. An all-carbon fork is generally not only lighter, but more flexible. Having said that, I'm sure that there are all-carbon forks that are stiffer than bonded-crown forks.

If you are concerned with ride comfort, look at the saddle, seatpost, bars, stem, and tires. Run lower pressure on the tires, and you'll be all set.

It's a race bike. By race bike standards it has a nice ride. By touring bike standards it probably rides hard. Kinda depends on what you want it for. If you want a nice compliant ride to do centuries I'd no doubt choose a different bike. If you want a fast race machine that's capable of transmitting all your effort into go, but still ride well enough, it may be the bike for you.