The true benefit of the MaxxFusion is the computer chip which controls battery activation. Because of that technology you get great vapor production on the first puff without the need of a primer puff. Additionally, you get longer battery performance and regulated 3.6v output. Most KR808 batteries will vary in output from 3.2v up to 4.2v. This will cause variance in performance and may burn up your carto because it will "burn" too hot.
The Trifecta, made by a different manufacturer than the MaxxFusion, does not have the same battery control chip. Both, however, were made for Bloog at Leaford's direction.