I'd go for Sonic Blast/Dark Miasma. Mostly because I don't like bubble sets, and you can never go wrong with Dark Miasma. Also, I'm told Sonic Blast is good for soloers due to Siren Song, but I've never been much on soloing.
Everything in Dark Miasma is useful solo, while Sonic's bubbles are irrelevant alone. Siren Song from the blast set is useless on teams, while Torrent isn't exactly team-friendly either.
I've got a low 40s Sonic/Dark Corr and it is quite fun. I don't have any experience with Dark Blast so I can't comment on the opposite.
Oh and both sonic sets are very end heavy.
For soloing, Sonic/dark runs circles around a Dark/sonic.
Hi Gang,
many thanks for the responses, have decided on a Sonic/Dark 
I am looking forward to using both the new (for me) power sets and will embark on my journey aware of the end usage situation and plan accordingly.
Cheers
So many cats - So few recipes!
Age is of no importance,
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Sonic/dark brings great things to teams too. Huge team heal, team ressurect, lots of -to hit, -regen, and tons and tons -resist for hard targets like AV's and stuff.
Hi Guys,
am dipping my toes into the world of Corruptors and purely because I have played most of the other powers on other AT's I want to roll both Dark and Sonic on this one.
So which of the options can you comment on for me. Am mainly a soloist but usually do the 2nd build team role stuff on my alts.
Sonic/Dark?
Dark/Sonic?
Any thoughts, comments, experiences would be of a help. How they play, how they use the endurance et cetera.
If it comes to it I may actually roll both but would appreciate your wise heads pointers. Thanks
So many cats - So few recipes!
Age is of no importance,
unless you are a cheese!