My first SF had the pop off doors but I never took them off in all the time I had it. The SF is my winter tarp and the chances are I'm going to want to hunker it down at bed time, being able to close the ends off makes it much more cosy when it's blowing a hoolie.
My new camo SF has the doors attached, they're actually just an extension and different cut of the fly rather than added on. Easy to chuck up out of the way, I usually throw my door tie outs over my panel pullout shockcords and give it a couple of wraps.
I preferred the old shockcord and cordlock system on the door tie outs of the older models, the new plastic triangles just need a bit more fettling if you want adjustability, fine if not.
Get saving, you're gonna love it