Pros are probably still mostly using Serato or Traktor, but I don't think it's necessary. I used Traktor for a while but like Mixxx better. It's very good software. It had a lot of shortcomings in the 1.x releases, including stability issues, but I would definitely trust it for pro work today.
But i always loved, and still do, finding good tunes and then curating a vibe and a night. That's a great feeling. Free drinks help as well ;)
Workflow is: drop from beginning, play+tweak til roughly beatmatched, rewind to beginning and needle drop on first beat again, then begin fading into the mix
I think you can do that in Mixxx using the "cue" button. While playing, tapping "cue" will rewind to the beginning of the track and pause; pressing "cue" and holding it down will preview from the beginning. While previewing, you can press "play" before releasing "cue" in order to continue playing; otherwise, releasing "cue" will rewind to the beginning and pause.
So, you'd use a similar workflow: play from the beginning of the track and tweak until beatmatched, then press and hold "cue" to rewind to the beginning and start playing from the first beat. If it works, press "play", release "cue", and bring up the fader; if it didn't work, just release "cue" to rewind, then try again.
Thanks though! I still like Mixx, no hate here. I just need to spend some more time with it