Differences in FCM and IB?

I have automated with NT through AMP in the past and connection was rock solid. A very long time ago (many years), I tried to execute through MC through IB and experience was not good (got my positions messed up).

I am looking for new broker that will work well with MC. Has anyone tried both MC connect to IB compare to MC connected to dedicated FCM like AMP? Did you find that connect to AMP or FCM was more solid? What's the most solid connection you found?

Please share experiences because IB has a lot of products offered to trade but if FCM offers a better connection I'd rather go through them.

Any experiences for those of you who have traded through IB and a discount FCM? Did the discount FCM work better for automation/futures?

This is my experience.
AMP+Rithmic+MC much more stable and faster than IB+MC