Sigma EF-530 flash for a100

[demonsmasher]

Looking at getting a flash really soon. I noticed on adorama website they have a Sigma EF-530 listed not in stock yet. Dose anyone know how this compares to the Sony 56 model? The speck for the sigma is as follows. http://www.adorama.com/SG530STSO.html

Guide Number	@ 24mm - 92 ft / 28 M @ 28mm - 95 ft / 29 M @ 35mm - 102 ft / 31 M @ 50mm - 132 ft / 40 M @ 70mm - 149 ft / 45 M @ 85mm - 158 ft / 48 M @ 105mm - 174 ft / 53 M
Power Source	Four AA alkaline or AA NiCd or Ni-MH (Nikel Metal Hybride) batteries
Variable Power	Full to 1/16
Recycle Time	6 seconds (when using alkaline batteries) Approx. 4 seconds (when using NiCd, Ni-MH batteries)
Number Of Flashes	Approx. 220 flashes (when using alkaline batteries) Approx. 100 flashes (when using NiCd, Ni-MH batteries)
Illumination Angle	Automatically set in accordance with the focal length of the lens, in a range from 24 mm to 105 mm. Also covers the angle of a 17-mm lens when used with the built-in Wide Panel.
Bounce Angle (Up)	0, 60, 75, 90 degrees
Bounce Angle (Right)	0, 60, 75, 90 degrees
Bounce Angle (Left)	0,60,75,90,120,150,180 degrees
Tilt angle (Down)	0, 7 degrees
Dimensions (W X H X D)	3.0 X 5.5 X 4.6 inch / 77 × 139 × 117mm
Weight	10.8 oz. / 305g (without batteries)

The sony is: http://www.adorama.com/ISOHVLF56.htm...ony&item_no=16

Type:	Auto Locking Accessory Shoe Connection
Guide Number:	56 (at 85mm position, ISO 100)
Zoom Range:	24mm to 85mm, 17mm with wide panel
Bounce Capability:	Able to bounce up and down
Swivel Capability:	Yes, left and right
Auto Settings:	Auto zoom
Dimensions (W x H x D):	3 1/8 x 5 1/4 x 4 inches (W 77.5 x H 131 x D 99.5mm)
Weight:	Approx: 13.1oz (370g)
Special Features:	High accuracy ADI in combination with D Lens (lens with built-in distance encoder) High-speed synchronization feature for synching with high-speed shutters
Power supply	AA batteries
Wireless Flash	Yes
Wide Angle Panel	Covers angles of field up to 17 mm lens when using included wide panel

Any help from you guy with more exp would be great inwich flash will be better.

[SmartWombat]

There is not much difference between them.
The Sony is slightly more powerful, GN 56 instead of 53 at 85mm.
The Sigma zooms to 105mm not 85mm, so will get more light on a distant subject.
The Sigma does not mention support for ADI, so in auto mode the Sony might be better.