Hi Joe,
I have been using a Nissin Di622 as I couldn't afford a SB600 at the time, and although I couldn't fault it I have now bought an SB600 and I think it's great, as I've said on here before though the only thing I wish Nikon had done was to build in a piece of white plastic which lifts up to direct the light forward when using the gun straight up. I don't think you will be disappointed though, but have you considered getting one off here as I did for less than the £149 you mentioned ? I can't comment on the other Nikons mentioned.