I actually used both last year (this is year 3 for me for the Compiler). Both are very nice programs (with the DD being a little more refined by being a VB program and it is free). Big fan of the Compiler (great job Mike!) also though. Since I'm an advanced Excel user I end up with the ability to tweak it a bit. Draft buddy is a nice add on and I prefer using that to record/publish my league's draft results.
My main complaint on all these products is I don't have all my league's scoring options. Return yards & TD's for individual players & 2 pt conversions really impact the WR's in my league (and some RB's). I like to use both programs for the varied projections and add my own tiered rankings (A, B, C, etc) as a 3rd (& main draft board) source. I use the data in the Compiler & DD to bounce against my rankings at pick time (along with other site & historical data). That seems to work best for me and produced 2 Championships last year (redraft & keeper league). I usually finish 1st or 2nd in my leagues (2-4 per year)........with the occasional aberration.
I think both programs/sites do a very good job with their projections & tools and have very well informed/knowlegeable football fans................ but I have found over the years not to discount my own rankings (sometimes they are just as good).