Mine

Emc2's trajectory control has been totally rewriten.  It has fixed quite a few of the bugs from the original emc planner. You can read about it here.
http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?TrajectoryControl

It supports g61, g64 and g64 px.xxxx(blend tolerance mode)
You probably want to try blend tolerance mode as emc takes the all the short line segments that fall within the P number and create larger line segments.  

I have no experience with mach to compare.