American big diesels are in same line with European competants; our local truck manufacturer is using Mack's and Cummins' engines and in some cases Eaton-Fuller gearboxes (thought usually synchronized ZF's AFAIK).
However the frames, brakes, suspensions and other technical equipments and ergonomy was far from what Mercedes, Scania and Volvo had in their models at least ten years ago; maybe they're better now.
I've driven (just for test when I had possibility) new MAN, Volvo F16 & F12 and Scania 142 (+ancient 110 Super & 140).
New are very impressive cars; better ergonomy than in ordinary sedans with a dashboard surrounding driver, gear robots, top of the line audio systems, leather steering wheels, alu wheels around + disc brakes... bling-bling
btw Scania made crashtests with trucks already in seventies.
btw2: I saw US embassy's truck maybe week ago; it looked like it was from seventies... or from Russia.
http://www.kolumbus.fi/staga/25082005.jpg