Singer is a very good director, he made poor choices with SR and failed, but he did a good job with the X-Men movies (among others). He can get the job done with a BSG movie, it will depend on the quality of the script and the casting.
I don't think he's all that anymore.
It may surprise you, but half of his films haven't performed well:
Superman Returns,
Valkyrie,
Apt Pupil: they either lost money outright (AP, which made only $8 mil or so) or barely pulled in more than their production budgets (SR and V).
The other half did much better:
The Usual Suspects, cost about $6 mil, pulled in about $24, this was also a huge critical success and won some awards.
X-Men, cost $75 mil, raked in $157+ mil
X2: X-Men United, cost $110 mil, made $214 mil
So,
his record is a bit on the uneven side.
I don't know why he'd do a film like BSG. It's the worst kind of desperation to make a movie like that.
I read an interesting article online, thanks to twitter, but part of the major problem in Hollywood is that everyone is scared. Scared to take risks in case they fail, so they pick what they think are safe bets that don't turn out well.
The current spate of toy based films is only because Transformers worked and made money.
Despite what are probably high expectations, I don't think the Asteroids, ViewMaster and Lego properties are set for the same sort of success.
Despite the success of previous films based on TV series, I don't think BSG will follow suit. It's already been done better on SciFi.
Him taking this project now hints of desperation.