I have the Sunpak 544 and use it with my C-2100.
I don't have any experience of the Vivitar, but other members on
this forum like it a lot, and the photographs I've seen with it
looks good.
In my opinion the Sunpak has the following advantages:
1) VERY powerful
2) Built-in bracket (saves $20-40)
3) Very versatile auto settings (1/2-f-stop increments; F2.8 to F8
on ISO 100)
4) Full manual adjustments (correlates to about 1/2 f-stop from
full power to 1/64th.
5) 90° Tilt; 180° Swivel (can turn facing backwards)
6) Very consistent and accurate auto output.
7) Very fast recycle time (
8) Can strobe up to 5/second (and maybe more)
9) It makes you look professional!
10) Very good battery life (I took over 200 and batteries was still
good)
Disadvantages
1) Large size
2) More expensive (maybe)
3) Takes 6 batteries (I charge them 3+3 and has not had any problems)
Look at my pbase galleries - all the flash and fill-in flash
pictures were taken with this flash.
http://www.pbase.com/spannie
Also look at this threads (if you haven't yet).
http://www.dpreview.com/forums/read.asp?forum=1008&message=2375945
http://www.dpreview.com/forums/read.asp?forum=1008&message=2429034
If I can sum up why I really like this flash, it is that it does
not limit you in any way (i.e. you can adjust the flash to what you
want and you don't have to compromize or adapt to the flash), and
it is accurate and consistent (i.e dependable).
You can't go wrong with this brute!
Spannie
I'm stuck between these 2 flashes...I 've read great things about
both here. If its a tie I would lean towards the 285hv since it
uses 4 AA batteries and is cheaper.
I would appreciate the thoughts of experienced users here
--
David
[email protected]
--
Spannie