Aluminum profile and alu plate 1500mm x 600mm x 150mm working area, first cnc.

[JAZZCNC]

This is the vital fact, I have found the negative side of this equation - low accel/high speed and what it does with Mach3 is give terrible contour following because of the constant velocity engine Mach uses. Its not just a little bad, it's the difference between turning out scrap and turning out parts.

I have retuned with lower speed as higher acceleration was too jerky on my old Bridgeport conversion and its all working nicely now.

Exactly Dave. Like all things in life Balance is the Key. Good machine is tuned with nice balance of speed and Acceleration.
Getting wrong either way will have negative affect on machines performance in different areas of work type.

For instance your case of high feed but with low accelration caused corner rounding. This was on relatively small parts with tight radius on small machine. On larger machine like router with larger parts say doors or shaped work tops etc with no or large radius sections then high feeds with Lower Accel will be ideal.

Different strokes for different folks, Or machines in this case.!

This is why Mach3 and some other Control software will let have you have different profiles which can be used to have machine tuned or setup differently to optimise the type of work your doing.