I've been offerred an old 4-bits/pixel greyscale Xterminal.  Aside from the
"real people have already upgraded to RISC architecture R5 servers", do I want
this Xterminal? 

I'm concerned about the 4-planes...I've only ever heard of 1 (mono) and 8
(colour) planes -- will I have any concerns with this 4-plane unit? 
[Specifically related to 4-planes vs 1 or 8]

Thanks!
-C-