Pro Tools is the industry standard. The majority of recording facilities, especially major ones, have their setups routed through pro tools. It is used for recording and mixing, pre vs post production. Ableton is a production DAW. Great for composing tracks and ideas. It is great for mixing too, however generally if you send of a session to someone else to get mixed, you will send the PT session or the track outs of the song.
That being said, it cannot hurt to learn it. If you want to produce and do some general mixing inside Ableton, then great. I won't say PT sounds better than Ableton, thats preference and the ability to mix well.
Noah "40" Shebib built a recording studio in Toronto structured entirely around NI. So the progress of using other production based DAWs as the main hub is growing. Pro Tools is still the industry standard.