there are several things to consider when choosing a Braille display nowadays.
1. If the display is going to be used as a stand-alone device, will the language in question be supported by a possible speech synthesizer?
2. Does the screen reader in question have the necessary Braille tables to display said language?
Most of the time, you can find Braille tables elsewhere if that should not be the case. JAWS used to habe jbt files you could copy to have them show up in the Braille translation combo box, but more recent versions of JAWS and or NVDA use recent Liblouis translation tables.
I suppose the same would hold true if you were using contracted Braille in whatever language, but that's a question of settings and Braile tables again.
3. If the device has stand-alone Braille input, how good is its back translation from contracted Braille into standard writing?
Some devices offer a feature where you type contracted words and these are then translated back into normal words. This is very useful if you have to type a lot of text fast.
I cannot tell you what display offers the best or good results there, since I don't own anything super recent.
Note: I'm mostly refering to devices that are computers themselves here, notetakers with interpet capabiities, etc.
When it comes to keyboards, some people may prefer actual keyboards with the symbols on them, provided they have enough vision to make out anything meaningful.
There are companies that sell keyboards with larger font sizes for vision impaired users.
As for me, I completely killed the US English keyboard and am just using the German and Spanish ones.
The US keyboard has all the different punctuation symbols elsewhere when compared to the rest of Europe, so Spanish is very close to the German layout in that regard, just y and z are where you'd expect them on a US keyboard.
Another benefit of the Spanish keyboard is that I can produce all sorts of accented letters fairly quickly.
I memorised the layout spending some time in Spain, others may have different approaches to multi-lingual input.
What language is your client going to use?
Braille displays also have dot commands or menus where you can change character sets and Braille tables.
Hope that was somewhat helpful.