Thanks everyone. . . it looks like I've just been a hair on the unlucky side.
I've currently got 9 factors in 4282 WU or about 1 factor every 475 WU, which would seem to be less effective than LLRing for SoB, but it looks like even if the 57P to 58P range doesn't find any more factors in the last 45 WU it'll still be finding one factor every 403 WU which shows that my computer's better off Sieving, just like I figured it should be.
I guess I can look forward to a rush of factors. :-Þ (I know that's not how statistics work, but eh.)
Thanks all for the quick replies.