I got my PCNC1100 in July 2011. The first job I ran had some heavy cutting with a 3/8 3 flute end mill in some 6061 aluminum. I tried to take a 1/2 inch depth of cut making a slot.
Doing that, the cutter pulled down and went through the bottom of the part.
I learned then that the best way (for me anyway) was to create a drilling routine and do the heavy metal removal with the Z axis.
As for run out, my holders all run within a couple of tenths or closer.
When I bought my machine I bought 4 each 1/4, 5/16, 3/8 and 1/2 inch set screw holders ans 6 each ER 20 and ER 16 collet holders.
I learned when I owned a real CNC shop that you can't have too many tool holders. I had 2 CNC mills and I had 75 CAT 40 tool holders.
I run my PCNC1100 12 to 14 hours. EVERY DAY. Will I get over that? Probably not.
You can buy GOOD PARTS or you can buy CHEAP PARTS, but you can't buy GOOD CHEAP PARTS.