On this page
http://video.stackexchange.com/ques...big-three-video-editing-nle-software-packages you'll find 2 polls with 2 different outcomes, but with one thing in common: Avid scores low numbers
Unless you know who is responding to those polls, the results are meaningless. If most of the respondents are serious amateurs, semi-pros or those working in very low budget sectors of the industry then you'll find few who use Avid simply due to the fact that it's far more expensive. If the respondents are commercial post houses, major prodcos or studios then Avid will be at or very near the top.
... what's mostly used in the major studios ?
Sonnyboo has already answered this question, Avid is by far the most widely used in the major studios, pretty much to the total exclusion of any of the other NLEs.
But if it varies, then point made that it's just a tool that does the same thing and it depends on the individual.
It does vary (although not at the major studio level as mentioned) but the fact that it does vary does not make the point that all NLEs are the same. In fact, it's evidence of the exact opposite! All the main NLEs do have the same basic editing functionality. However, how easy/quick it is to employ that functionality varies from one to another and functionality beyond the basics also varies. Avid for example has a lot of network features not present in other NLEs. For example, Media Composer can be "locked" to ProTools (the software which dominates commercial audio post). You can have a network of ProTools computers, including a "video satellite" machine (running Media Composer) all locked together and controlled from one "master" ProTools rig. The advantage is that the video does not need to be rendered and imported into ProTools and, if connected to a wider network with other Media Composer stations, updates to the Video Satellite station can be near instantaneous, say in the case of offline media becoming available or media being updated. An extremely common occurrence as the VFX/CGI departments are usually working at the same time as the Audio Post departments. This can be a massive and invaluable time (and logistics) saver and is just one of the network features of Media Composer. Other network features are more aimed at the big Post Houses which may have as many as 100 or more editing "seats", although it depends on the type of work being done at these post houses as to how useful that functionality is. At the amateur and no/nano budget level, pretty much none of this particular area of functionality is of any use/consequence so then it becomes more a question of which functionality you do need, which NLE are you most comfortable with (makes that functionality easiest/quickest to apply) and commonly the relative cost. Premiere for example makes it extremely easy (relative to other NLEs) to transfer materials between certain other commonly used filmmaking software, After Effects for instance.
As you're already familiar with and like Adobe products, Premiere would seem like the obvious choice for you. If your goal is to become a professional pic/video editor then you would probably best be served by having a very good working knowledge of both Avid and Premiere and a working knowledge of FCPX certainly wouldn't hurt your job prospects either!
G