Had round column, seig, now using Enco RF-45 since 2009.
Have also used Bridgeport, Lagun, mills, big ones.
There were some key parts missing on the column, when
replacing the bearings, a year ago (machining some heat treated and some not heat treated lathe tool holders) . The guide pin, that fits into the column long slot,
was not there.
There is also about .2 up down of head, when using the fine fine. Its those gears
back lash. So, usually never use it. Just lock the column, use the quill or crank
head up or down.
Another poorly designed feature was column lock, replace with brass and profile
more closely match's column. Was developing quite a bit of scoring on column.
The crank for head is on right side, believe Grizzlys are on left side, so your spider, thing that moves column up down, is sort of in your face, on my mill.
Another gotcha are those screw in pins to align R-8 collets in spindle. Spindle is not heat treated on mine. Spun a collet, sheared those pins. Replaced those pins,
2 holes for pins on mine. Noticed some R-8 collets would not fit up good. Bridgeport has a nice key to guide collet into spindle. So, I tossed the pins. All my collets fit
now.
Got a great table with 4 slots. Handles are aluminum...sort of cheesy. Check run out
of spindle when first got it, checked after replacing bearings, less than .001.
good luck
Charl