I just got an SB-28 Nikon speedlight and I'm using it on M or A mode... very nice. I got it for $50 and it's working great. I was deadset on getting a Vivitar or Sigma, but then I saw this, researching a bit, I think it's a very good buy
I don't miss P-TTL since sometimes my photos turn out under or overexposed. At least in manual or auto mode, you can adjust accordingly. With a built-in bounce card, wide angle adaptor(?), a back LCD, and bounce and swivel capabilities, I'm very much happy with my purchase! Thanks for the replies!