Nissin Di622
Mk2I've got two of the Mk1s and they are cracking units for the money, the reason you want the Mk2 is because the Mk1 would only sync with the pre-flash so you'll have to be using i-TTL or whatever canon call their rubbish, this meant you couldn't sync with manual flash, there was also issue with the flash going into standby when on non-slave mode, the shoe contacts being disabled in slave mode. I modded mine to get round these problems, and about 6 months later the Mk2 was announced.
Really you want a proper canon one, as you'll get genuine canon TTL metering, better AF assist, Auto FP etc, but you will be paying alot more for a canon unit.
Or are there any advantages to buying a Canon flash gun even though they seem very expensive compared to the rest.
the above really, a canon unit will produce better results that an after market, the same what the genuine glass does. I found the i-TTL on the nissin would be slightly over powered, compared to the Nikon flash; if you're using these for off camera then the light will be the same (daytime balanced) and the only difference will be the level of control (power settings) and the guide number (how bright a light it can produce).
