A hard choice . . . . .
. . . . but as others have said, you will probably love your Spyder whichever one you choose.
Take more test rides - that will give you more experiences to base your decision on. Your first rides will have no many new sensations you probably will not notice some of the finer differences.
I ended up with the SE5, I found, for me, the ergonomics of sitting position were more comfortable when I didn't have to keep my foot on the shifter. I didn't realize that until my 3rd test drive. I probably would have adjusted, but that was what tipped me to a SE5.
After 45 years of motorcycles, my clutch hand still wants to do something. So, sometimes I find myself "clutching" my SE5 and downshifting when I really wanted to upshift.
Yup, you cannot shift into neutral if you are going more than 2 miles per hour. A couple of times, when down-shifting to a stop light, the bike has downshifted at the same time I have and I have ended up in Neutral. Something of a surprise when I (don't) take off when the light goes green.
Not having to back-off the throttle to shift is a hoot, and still usually brings a smile to my face.
On the SE5, you have to set the Parking Brake when you are parking the bike. If you don't, you get an alarm. BUT, you have to remember to release the Parking Brake when you start your ride (there is a reminder and flashing light on the dash - no audible alarm when you go into gear). Something really different from all the motorcycles I have ridden. Hands-down, the scariest experience I have ever had on any vehicle was when I took off from a parking spot to merge into traffic with the Parking Brake on.
One final thing, most people call the SE5 an "Automatic". Not exactly. The E is for Electronic vs. the M for manual. You shift. The computer can shift (seen most often in downshifting) and it assists you in handling the clutch work. There is no doubt in my mind that the SM5 is a traditional motorcycle experience and the SE5 has less of the coordination and control found in that hands+feet+mind+machine relationship. If I had to ride a SM5, I would and I would enjoy it, but, I would much rather have a SE5.
Again, do more test drives. If you like the overall Sypder experience, I don't think you can go wrong with either the SM5 or SE5. Multiple experiences test drives will "tell" you which feels the best to you.
Tom