lil nut,
I've recently switched from conventional stance to sumo stance to see how I went and I found that there is quite a lot more hamstring used in the lift compared to the way I pulled conventional.
For me personally sumo is a lot more technical than conventional and good hip mobility/flexibility is needed to get the maximum benefit out of the stance.
Essentially the idea is to push your knees back to open up your hips and get them (hips) as close to the path travelled by the bar as possible, this in turn straightens up your back.
Instead of trying to push your feet through the floor like conventional, you should be trying to spread the floor apart, this will engage your quads and prevent your hips from leading the lift and avoid you doing a SLDL.
That being said, like conventional there are many different ways to skin the sumo cat it's just a matter of finding out what works best for you through trial and error.
Here's some video's to keep you entertained
Ed Coan - Deadlift 901 @ 220
[ame=http://www.youtube.com/watch?v=-dpRChwpmaM&feature=related]YouTube - Ed Coan - Deadlift 901 @ 220[/ame]
854 Ed Coan 198 at Gus Rethwisch's Hawaii meet 1985
[ame=http://www.youtube.com/watch?v=QNPXmiWCBi0&feature=related]YouTube - 854 Ed Coan 198 at Gus Rethwisch's Hawaii meet 1985[/ame]
Ismo Lappi 340kg Deadlift
[ame=http://www.youtube.com/watch?v=BIOK_fF0w2s]YouTube - Ismo Lappi 340kg Deadlift[/ame]
Jarmo Virtanen 340kg DL
Sami Nieminen deadlifts 305 kg for 75 kg classin Finnish Powerlifting
Championships
[ame=http://www.youtube.com/watch?v=1d8BHTrYGyI&feature=related]YouTube - Nieminen DL 305 kg[/ame]
Oleksandr Kutcher 2002 IPF Mens Open World Championship 315kg/694lb deadlift
@ 165
[ame=http://www.youtube.com/watch?v=63GGbznSw8w&feature=related]YouTube - Oleksandr Kutcher 315kg/694lb deadlift @ 165[/ame]
Furazhkin deadlift
320kg@75kg
[ame=http://www.youtube.com/watch?v=p34TX2zNy4k&feature=related]YouTube - Furazhkin deadlift 320kg@75kg[/ame]
Roman Voroshylin 365kg 05 IPF Worlds
[ame=http://www.youtube.com/watch?v=gwxNdz-ZfrQ&feature=related]YouTube - Roman Voroshylin 365kg 05 IPF Worlds[/ame]
.
belayew 365kg deadlift 90kg bw
[ame=http://www.youtube.com/watch?v=wrwVWk-eQ44&feature=related]YouTube - belayew 365kg deadlift 90kg bw[/ame]
Andrew Belyaev "Battle of Champions" 380@ 92 RAW Deadlift
[ame=http://www.youtube.com/watch?v=qZYF7lWG9ok&feature=related]YouTube - Andrew Belyaev "Battle of Champions" 380@ 92 RAW Deadlift[/ame]
Andrey Belyaev 362.5kg (799lbs) deadlift
[ame=http://www.youtube.com/watch?v=EZhvzYlYBlY&feature=related]YouTube - Andrey Belyaev 362.5kg (799lbs) deadlift[/ame]
Papazov deadlift 382,5 kg Total 1102,5 kg - 125
[ame=http://www.youtube.com/watch?v=Kd0I2I8Pm2E&feature=related]YouTube - Papazov deadlift 382,5 kg Total 1102,5 kg - 125[/ame]