Here in Italy we have not many Underwood 'Olivettis' , understandably. There are probably more model 5 still lugging around than model 450 (my '5' is a 1913 model, 111 years old and God knows how many revamps, and still working fine). So .. I think I never saw a 450 in the flesh. But honestly, this time the plain, unassuming Underwood is nicer-looking than the fashionable Sottsass/Von Klier 'Studio' sister. Never liked that much the Valentine and the Studio 45, despite the cult status of the former. But I find their computers and calculators and standards terrific! Olivetti Logos desktop calculators in particular are piece of art imho. The 450 looks every bit as sharp.
I think the cinematic of the 45/450 is close to that of the Lettera 35, thus still the older Lettera 32 ultra-portable made bulkier, and some plastic part starting to appear, like carriage knobs, lever tops and margin tags. Still great user machines: my father used his 35 for decades and I still have and use it.