Hi Johnnie,
I used Logic since V.2, then 4 years ago I was forced to start operating a commercial studio based around Pro Tools, which I now use every day, so I have a pretty good sense of both apps. Pro Tools is awesome for editing audio clips and sounds great for mixing, but Logic is much more musical, IMO, so I still use L8 for composing music, then stem out the tracks and mix in Pro Tools. I know that if you get used to using Pro Tools for composing, you can feel quite comfortable (I'm going to guess that's partly because of the great sound) but after all those years on Logic I'm just waaay faster composing on it. I love the huge selection of instruments available in Logic, the ease and power of EXS24 as a sampler, and the manipulability of musical arranging, chopping and moving pieces around as necessary. In Pro Tools I prefer the power of the automation and, as I said, the sound. (When I first started, I took a project, stemmed out the tracks, then imported them into Logic and Pro Tools one after the other. Combining the tracks flat, with no effects, the Pro Tools mix sounded considerably better. Having said that, I haven't tried this for 4 years now, and maybe the mathematics in Logic have improved..?)
I'm curious, why did you ask the question? Are you considering changing, or are you just exasperated that so many other composers you meet don't use Pro Tools?