We have a Bristol 45.5 which is very similar. Have a particular look at the tankage. The quality of the materials is exceptional - our water tanks are Monel, but there are issues with the welding and attachment of hose fittings. On the 45.5, there were two very large fuel tanks that generally have had to be replaced and replacement is a very costly undertaking since you need to take apart a lot of the interior to get the old tanks out. Other than that, I am not aware of issues particular to these boats so it is more a general question of the quality/upkeep of a particular boat. Also look at where the anchor windlass is located. Our windlass was way forward, in front of the ondeck locker. This meant that the chain fell onto the slope of the overhang and it was not steep enough to fall backward into the chain locker so it castled and jammed. Someone had to be in the v-berth to pull the chain backward with a boat hook as it came in. That was a major PITA. We bought a new windlass and positioned it just after of the decklocker so the chain has about 4' to drop. Also, gets the weigtht back which is a good thing.
Finished the circumnavigation in early February in Grenada. Have to work on a book project for the next several months so the boat will be waiting for next year.