Best thing you can do is try the demos of those programs (where available). If you peruse the music tech forums like Gearslutz I think you'll find that Sonar is spoken very highly of among seasoned DAW users. I've heard Mac users lament that no Mac version is available, put it that way.
They all have their ups and downs. With regard to the "top" DAW's, a lot of their "top" status has to do with how popular they are. Things like Abelton and Reason have more street cred than Sonar, mainly because they are known to be used by big names in the world of electronic music. It's kind of like back in the day when most producers used Atari ST's in their studios. You could do exactly the same thing with an Amiga, but the Atari name became synonymous with music production more so than the Amiga, so that was that - nearly every hobbyist went for the Atari over the Amiga. Same thing with Macs versus PC's in the graphic design world.
To me, Sonar is an ideal balance of audio recording and MIDI sequencing. Abelton and Reason are more geared toward MIDI, while Pro Tools has always kind of lagged behind in the MIDI stakes but is more used for audio. I used Pro Tools for a while and it sucks compared to Sonar, despite being the "industry standard." Sonar seems to be the best of both worlds. But it depends on what kind of music you're into. I've heard it said that Sonar's automation capabilities aren't fully up to the task of producing Dubstep, for instance, but I don't quite know what that means.
You could also try watching a few YouTube tutorial videos for each DAW, get an idea of the workflow and figure out what the advantages of each one are.