Great write up I found on M4Carbine.net from Trident82.
High Speed 2 stage match triggers:
DMR- First Stage: 1.3 - 3 pounds (2 pounds nominal) Second Stage: 0.5 to 1.5 pounds
Service- First Stage: 3.2 – 5 pounds (4 pound nominal) Second Stage: 0.5 to 1.5 pounds
Match- First Stage: 1.3 – 3 pounds (2 pound nominal) Second Stage: 4 to 14 ounces
**same actual trigger, just different springs to allow the three diff. pull weights. These are arguably the best triggers for competition, bench, or precision shooting. The break will read your mind. The break on this trigger is like an icicle breaking.
SSA - two stage trigger has a pull at about 4 1/2lbs and by most is considered the most reliable trigger on the market and is a perfect fit for any duty or hard use AR. The break on this trigger is like a carrot breaking.
SSA-E - two stage trigger that unlike what most might assume is not the actual same design as the SSA and doesn't just use diff. springs...its actual engineered differently. This trigger has a pull at about 3 1/2lbs, and has a candy cane like break of the trigger.
SSF - two stage trigger that USSOCOM uses and is the select fire version of the SSA. In S/A it functions as a two stage, in F/A it functions as a single stage.
S3G - the new hybrid trigger featuring a fast reset and the break just disappears. Plenty of discussion on this unit already and I am not that familiar with the 3gun models.
Super Dynamic line of triggers: Trigger bow moved 1/8" forward and features an almost flat faced trigger w. a gentle curve.
SD-C - two stage trigger that has a pull of about 4 1/2 lbs. and is comparable to some degree to the SSA.
SD-E - two stage trigger that has a pull of about 3 1/2lbs. and is comparable to the SSA-E. This trigger has a amazing break.
SD-3G - plenty of discussion already on this trigger and its comparable to the S3G. Its a hybrid trigger and has a very fast reset and overall is a lightning fast trigger to operate.
On another note...after SHOT, GA is due to release a economical option called the Super 2 Stage or S2S for those who usually are relegated to buying an RRA 2stage or the like and it will be very similar to the SSA, just about $50 cheaper retailing for IIrc around $125.