SE for Me see the reason below :-
For me and maybe a few others with a left leg disability the SE Transmission has been a godsend We can ride the Spyder with no alterations needed
I had polio when I was a child which left me unable to use my left leg I wear a KAFO (Full length support)
I rode 2 wheel motorcycles adapted to allow me to use a hand change to select the gears as the leaver was on the LHS (All motorcycles apart from some British and others had it on this side) with the brake lever on the RHS
I had a rod made to connect to the Gear leaver and used my Right hand to push/pull this leaver to change gear
in the last few years I discovered the Kliktronic electronic push button gear change and this was fitted to my last 2 wheeler BMW K100LT
See
http://www.kliktronic.co.uk/lik
When the Spyder came out with the SE Transmission it was so easy to ride and I have not had to make any Adjustments/Alterations - I could ride a SM But would need to fit the Kliktronic anyway so this would add to the cost
So for me the extra cost has not been an issue
For safety the SE ensures I am in the correct gear and is useful should I have to do an emergency stop the Spyder will be in 1st gear ready for me to carry on
I think a test on both so you compare both side by side - Decide which will suit you best and if planning to keep the Spyder sometime go with what will suit your style of riding in the long term
Either way enjoy you your choice just need to decided on Model, Spec, Colour etc
I am still riding my 2010 Model and will upgrade in about 2yrs time so I have plenty of time to make my mind up but by then I suspect they may be even more choices to make such is life