With all due respect I completely disagree with the opinion of the $999 Samson Milestone.
The bike is decked out with full 11 speed 105 components, including the bottom bracket and wheel hubs. Very good gear.
The hubs are laced to 32 hole R450 Alex rims. Nothing special but solid and reliable. I've been riding these rims on occasion for a couple of years now on my wet weather and trainer bike. They aren't race light but they are good, reasonable quality, training grade, distance rims/wheels.
FSA stem, bars and seatpost. Again, nothing flash but not cheap garbage. Nothing much (frequently) goes wrong with these parts.
The frame probably isn't anything special but if it breaks a replacement such as the aluminium Ribble
Winter Audax 7005 can currently be had for $156.07 delivered, an almost indestructible and well regarded frame. A large friend of mine (90-110kg's) has been riding one hard for nearly ten years with no problems.
I also own bikes fitted with Dura Ace, Ultegra and Sugino ensembles, flash wheels, the whole caboodle. My wet weather bike is very similar to the Milestone, a Cell Bikes clone, almost identical. The wet weather/trainer bike has been thoroughly thrashed but well maintained. It rides very well and had zero problems, something I can't say about 2 five times as expensive Giant and Cannondale bikes. Both broke, one replaced on warranty, the other a full cash refund.
Given the choice of the new, warranted Milestone or a second hand, unknown, potentially troublesome second hand bike I know which I'd choose.
I took the new bike option on an almost identical Cell bike and haven't regretted it.
Put some decent tyres on it and the Milestone will ride nearly as well as a $5000 bike. My Cell does. Slight exaggeration, but there isn't much in it. I've been surprised and very satisfied with my cheap purchase.
BTW. I ride a Defy, as well as a TCR SL, a Cannondale CAAD9 and a steel tourer. Very nice bikes but I just wouldn't be confident buying second hand carbon or aluminium. That's just my gut feel, others may disagree. I prefer new and warranties. Bikes break all too frequently these days. In my experience I've twice needed that warranty.
A Nexus geared commuter and a mixed component drop bar bike is a completely different kettle of fish to the Milestone.