It is very functional and portable and no wires or power cords on the floor which is nice.
This gives you the freedom to not have your camera connected to anything so you are free to walk around and try different angles.
Don't worry about the your speedlites not being able to see your ste2, rembmer you can move the heads of the speedlites so your umbrellas will face the necessary direction and the body of the speedlite can face towards your ste2.
Another good thing is once you have this system setup (purchased) you can take it with you very quickly. Or if you are going for a hike and might need a off camera light what I do is just throw my little, light weight ste2 in my camera bag with one speedlite and go hiking and if I spot a flower or insect that needs some fill flash tada I have all I need to get the shot.
A major con, and one that is making me want alien bees or white-lightnings, is the lack of a model light.
Yes you can hit your dof preview button on your camera but it does not last long enough to do critical focus and this will eat batteries quickly if you do it alot. So you have to have some other small light on near your studio subjec to get correct focus and posing. Thus you have introduced a secondary light source that can sometimes make white balance a pain and make more post production necessary.
Also I shoot my speedlites on full manual and my 20D on full manual I find that the ETTL results in this setup tend to underexpose. So just use the manual mode on your speedlites and you select the exact amount of light you want, photography is all about the control of light anyway. The ST-E2 has a ratio feature that you can quickly adjust control over each light as another method of balancing key and fill.
Good luck and here are a couple of my favorites from this setup. Not anywhere near pro quality but I have only been doing this for a short time and not really dedicated to any one aspect of photography like studio lighting. So good results can be had quickly in skilled hands.
http://www.pbase.com/lundy/image/48225409
http://www.pbase.com/lundy/image/48235171
http://www.pbase.com/lundy/image/48546433
http://www.pbase.com/lundy/image/46873735
http://www.pbase.com/lundy/image/40731900
That was done with a Canon G5 (point and shoot) and this setup.
http://www.pbase.com/lundy/image/42628561
See no wires!
http://www.pbase.com/lundy/image/42670384
A personal favorite.
--
Lundy
'Sometimes the best part of wanting something is not having it.' ME 1994
http://www.pbase.com/lundy