~I've used almost everything that there is from Audacity, Cool Edit Pro (Now known as Adobe Audition), Mixcraft, Fruity Loops when it was online only, ProTools & some others I can not remember. I've used all the above to either record or make beats. I originally started off using FL though for beat making then switched over to Reason which is what I currently use.
FL is great it really is even though I didn't spend long producing in it. I think one of the reasons why it gets a bad rep is because almost any & everybody can get it easily & for some people that may ring to them as 'cheap' just like what @Breeze mentioned.
Thinking it gets a bad wrap for how "easy" it is. it's easy for any kid with a computer to pirate a copy and learn the general ins and outs of it within a few weeks or so. FL Studio gets so much more flak than it deserves, it's an amazing DAW.
It's kind of like the Virtual DJ & Serato wars where Serato is deemed elite to Virtual DJ because the vast majority started off using Virtual then probably migrated to Serato over time. Some argue Virtual is just a play thing or a start up software to give you a feel for djing but it's lame, it feels plastic or it doesn't look professional etc etc.
ProTools, Studio One & Logic are considered elite because we know professional producers or engineers in the industry who use them & probably made a hit record or hit album & that actually plays a psychological part on how we view a particular software. I mean yes our individual preference based on workflow, features etc ultimately would make the decision on what we use but knowing that our favorite producer or someone we look up to uses a particular DAW can sometimes influences that choice as well.