There are a few flat out misconceptions in a few of the other comments below:
Hitfilm is cross-platform.
Hitfilm can accept GH4 files.
Hitfilm can import Cineform.
As a VFX/Compositing program, Hitfilm is fantastic. For 3D compositing work, especially involving 3D models and particles, Hitfilm is actually faster and easier than its Adobe competition. For more stylized 2D/mograph work, AE is faster and more powerful.
The editor is still Hitfilm's weakness. It has the basic tools to assemble and edit, but that's about it. I do a lot of event work, so Hitfilm's lack of multicam makes in unsuitable as my editor, but round-tripping isn't that big a deal.
Hitfilm's biggest weaknesses (especially in terms of a full production pipeline, rather than one-man-band) are a lack of XML support and limited output choices. Mp4 is fine for Internet or Blu-Ray, but for master quality output you're limited on PC to uncompressed AVI. Mac users at least have Quicktime. There's also PNG and Open EXR image sequences. This does mean another bounce through outside software for other formats, but a slew of Hitfilm users on the forum are transcoding with MPEG Streamclip, or other software (some users are frameserving from Hitfilm to other encoders), so limited output formats are an inconvenience, not a deal breaker.
Hitfilm 4 Pro should be considered by advanced users as an additional FX Tool for their kit that has a few idiosyncrasies to work around. Beginners who don't have other tools would be hard pressed to find a better attempt at "all-in-one."