The function of the strobe depends largely on... what's its function? Sport, studio work, journalism? Which most-closely matches what you're likely to do with the strobe? I've been through a host of Sunpaks and Vivitars and Canons and monolights, they all have a "sweet spot" for their usage. There days I usually carry a small unit with my 35's -- a Metz 23C (just died! alas I think I was too rough to it) or a Sunpak 322 (old and a bit slow but with an easy-to-tweak power adjustment), since I tend to use both of them for improvisational fill light outdoors. Do you want wireless? Automated bounce? Or will you only use it in controled situations where you can pre-meter? How much light do you need?