The first time I rented an
ECV, I got a sunshade.
I *must* have sun protection; I have PMLE, and burn like a vampire in the midday sun if exposed. My family calls me "queen of the mole people" because I typically only go out after the sun reaches a certain point in the sky, year round.
I *hated* that sunshade. It got in the way - if I parked in front of someone at a parade or show, they couldn't see over it.
It made driving on and off the bus a nightmare for me - I don't know why, but that big old canopy just bothered the heck out of me going on and off the buses.
From that trip forward, I now just wear a huge, broad-brimmed hat, with my UV gloves, long sleeves, long pants, etc. and if things get really bad, we find a bit of shade somewhere. There are certain times of the year I don't even try to go to WDW, because I couldn't stand all the layers of clothes with the heat. September is just barely tolerable, and on this last trip there were many, many times when I overheated due to a combo of heat/humidity. Sadly, from this point forward, I will probably only be spotted from mid-October through mid-February at WDW.
With the kind of rain we experienced during our last trip (last week), that canopy would not have done a thing to keep the
scooter/driver dry.
Remember that sun shades can be a double-edged sword; it may protect you under a certain set of circumstances, but as the sun shifts across the sky it can limit the effectiveness of the sun shade. You may have some bus drivers that will ask you to put the shade down to go on and off the bus. CMS may ask you to either put the shade down, or move from certain viewing areas for parades and other entertainment events so that other guests can see over you. And finally, expect limited protection from any rain storm that is stronger than a sprinkle.