one thing people tend to forget if theses are really new,
you will need to age the reference ....
i had 3 of them used w some problems (x-former and a vfd) aged for years, recapped them, one did get a certification, and was perfect the others where just compared, and where still rock solid, had the rack mountable L4411a but at some point you do miss the front keypad

but man they where fast to settle and get/be ready
and grab or build an "duino" gpib interface, or lan to gpib interface we have in some thread and be happy.
sure some says they lack this or that, but they don't crash like more recent ones ... cough cough
personally I would avoid any 3446x 34475 models, some say okay some have problems, but others brand have quirks too. my personal 2 cents
a 34410a was a perfect upgrade for my oldies 34401 ... 1x vfd later loll sure the vfd can or could be a problem, but now many have been cloned for many models ...
but at theses prices mmmm i'm still doubting, for me a 300-350$ would have been perfect