I have definitely seen a few Hamptons on Yachtworld that were located in Europe. (I own a 658, which the 590 will be very similar, just scaled down a bit). I wouldn't let the fact that there aren't that many in Europe sway me to a Fleming 58. I have been around Flemings for a long time, and before I found the Hampton thought I would end up with a 658.
The Hampton Endurance is a lot more boat, and for less money if that makes a difference. It's just more modern in every way. Go into each engine room and tell me what you think. If you are young, it may not make the much of a difference. But older, it's huge. To get into the Fleming ER you have to open a hatch in the cockpit and then clime down a crappy little ladder, stoop over until you get through the ER door. With the Hampton, you walk down a nice set of interior stairs into standing height Laz and then into ER.
The Flemings are well built, well regarded. They deserve the recognition they get. Hamptons are not as well known but usability wise, I feel quite superior, and at the same quality level.
Like Fleming, Hampton uses all top quality components (many of them the same, actually). So if you need work on engines, transmissions, Sea Torque, pumps, stabilizers, generators, these are generally the same.
I'd pick the best boat in my price range for how I intend to use it, and what is comfortable and safe for us.