One of the nice things about moving on to Avid or Premiere is that you get to take advantage of both the improvements in software and the accompanying support of more modern (and consequentially evolving) codecs directly within the applications.
Both Avid and Premiere (at this point) are still are based on the non-magnetic timeline, so other than learning where the knobs and dials are, either will feel structurally familiar to you.
Adobe Creative Cloud also offers a suite of applications that do a fairly good job of integrating to each other - such as Audition for sound editing and Photoshop for image editing - as well as the queen mother of motion graphics applications, After Effects.
I've had to teach people to switch from linear, tape based computer editing to Avid, and from Avid to Final Cut Pro 6, and always the first two weeks on the new platform that are the hardest - but one you get it, you'll be very happy with the improved workflows.
I'm sure the same is true with FCP-X, but for me Premiere was the better choice.
MtD