My experience with Hinckley (modern) Triumphs is limited to the 1997 Speed Triple that I owned in 2005-2006 and the 2000 TT600 that I owned in 2008. So, obviously much more sporty and mechanically elaborate machines than the Bonneville variants. But they were both durable machines with great components and good build quality, which is a trait that any modern Triumph will share.
From what I understand, the 790 and 865cc air-cooled twins in the Bonneville family of machines is extremely robust and extremely under-stressed. It's very, very tough to break the things. 2009 + gave us fuel injection on them, which is the single biggest problem I ever had with them, as I simply hate carburetors.
They're not overpowering machines. But as I understand they do handle well, they're the lightest bikes in the middle-displacement cruiser class, and just generally work very, very well. Truth be told, the Speedie and the America are two of the only cruisers (along with the Victory Kingpin) that I would actually like to own at some point. They look nice, the ergonomics aren't quite as silly as some other cruisers, and there's a respectable (though not Harley-Davidson level) array of aftermarket parts for them as well. And as stated, you can get them for far less than a lot of competitive bikes, too.
I'd do terrible things to finally see a Speedmaster-sized bike with the 1050 triple wedged into it. They did it for a while with the Thunderbird/Legend/Adventurer and the 885 carbed triple about 10 years ago, but they stopped the "Classic Triples" series of bikes before developing them with the more modern engines. Shame.