I have often pondered whether, if I were to become a successful producer, I would play live sets or DJ sets. I think I would choose to play DJ sets, and here's why:
1) As a solo performer, it simply isn't possible to have much improvisation when performing a 'live' set. Yes, I know Abledon Live has revolutionised 'live sets', but I still beleive that you need at least 2 people performing in order to make it truly live - 1 person to operate the sequencer, and another person to operate the mixing desk/effects units.
A case in point is Alex Smoke (one of my absolute favourite producers) - I saw him 'live' (using Abledon) in Melbourne in both 2007 and 2008, and whilst both sets were incredible, there wasn't really much difference between them.
Contrast this with Underworld, who have 3 people performing at once - Karl Hyde singing and playing guitar, and Rick Smith and Darren Price operating the sequencer, mixing desk and effects units. I have seen Underworld live twice, I also own their 'Everything Everything' live DVD, and I have also downloaded several of their more recent live sets, and, amazingly, all of their live sets are completely different! They recently announced on their Facebook page that, during their gig in South Korea, they performed an improvised, 25-minute long version of Rez/Cowgirl!!! - just imagine how good that must have been!!!
2) Why would I want to restrict myself to just playing my own music? - there is so much good music out there, it would be a shame not to share it with the crowd in a club. Sure, I could also drop a few of my own tracks into my DJ set, but that's my choice - a DJ set would give me total freedom in what I play.
I think that people who belittle DJ sets are missing the point - the main skill in DJing isn't anything technical; the main skill is TRACK SELECTION, and it's a skill I rate very highly indeed.