This seems to be a common sentiment about their accessories. In buying only a mill my experience has been a bit of a mixed bag to be honest.I have the PM "High Precision" 5 inch vise. I like the size, but not very impressed with the vise itself. I have not done an accurate analysis of how far it is off, but I have a shim under one side to bring it to parallel with the mill table.
I would go for the GMT one...
On my previous 9 x 32 I had a Kurt 6", but I liked the 4" Glacern better,
the Kurt is big.
I would go for the GMT one...