Hi Andi,
I've used a couple of Brother Postscript printers with my OS/2 setup over the years. Once I had the printer driver adjusted (by importing the PPD) all settings are available.
The models are:
1) OLD - HL1650
2) CURRENT - HL5470DW
The only issue/complaint I have is that with both of these printers, when printing from Lucide (PDF doc) I occasionally get a PScript error at the printer, meaning: instead of a page I get an error page print out of some sort of PScript error.
No problem, I print all my stuff using GSView.
Both of these Brother machines support PCL6 (in emulation), so I supposed one could always try that if the native BR-Script3 does not work.