This pertains to the older boats which are the foundations the current models now rely upon:
Last year, despite my best advices, my brother purchased a '86 41 Viking convertible.
Overall, I found it to be a pretty darned good boat.
The biggest advantages he found (and I agreed with) were pricing and interior layout. For the amount he budgeted to spend, he could own a newer & slightly larger Viking. Also, the Viking interior was laid out much better than the Hatt, at least in comparison to the mid '70's Hatt's. I was impressed by the Yankee ingenuity that gives the Viking so dog-gonned much interior space. The wood work is fine with top shelf hardware. Also, the wiring is top notch laid out very well & with lots of looms throughout.
On the flip side, he was surprised to see that my 36' had not one, but 2 shaft struts per side, where his shafts are carried by only one per side. Also, after the purchase, he discovered some pretty severe wood delam in the lazarrette area that the surveyor missed. I also found weathered painted wood below deck in other areas. Although these weren't superstructure components, they were in need of redoing to prevent rot from occurring. From my experience, this isn't an issue in the older Hatteras'.
Also, although Viking Yachts will still take his calls (unlike Bertram), they don't have anywhere near the interest or customer service support in place to run with Hatteras.
There were other interesting comparisons as well, but these were the biggies.