Aero Wheels?
I vote, -YES-.
Here's my experience:
When I lived in the rolling hills of Tennessee... oh, wait, I'm still riding in 'em.
Four years ago or so, I invested half an afternoon of my free/riding time and
fabricated a set of cardboard rear wheel covers.
Roll-testing my bike down the hill that started at the end of the driveway
-the hill I rode twice-daily for years-
showed my bike computer about 8 miles per hour more speed at the bottom of the hill
and quicker accelleration than it ever did when it was stock.
Now, my bike is an original Sofrider V1, so it's heavier, shorter wheelbase, taller and aerodynamically
'dirtier' than any Vendetta ever made, so, keep that in mind!
Ride-testing the faired rear wheel on the open roads was a screaming success:
side-winds did shove the bike around, but the centre of pressure
-think sailboat-
moved rearward with the addition of the faired rear wheel.
That made the bike self-correcting.
The added stability alone was worth it, worth it and worth it.
The added weight was, well, added... but I never noticed the difference;
neither did my bike computer.
My average speed improved; downhill and flat speed improved a lot.
I've gone through two sets of home made rear wheel fairings and have
put a lot of miles on my present set.
The cardboard prototypes shredded one day, in their first and only week in existence,
on a long and gusty sretch of downhill road.
My first 'permanent' wheel covers lasted a few months;
the door I'd made to fair access to the valvestem blew open & shredded the rest of the
cover.
My current wheel covers are pretty old now... I've repainted them once, so far... so good.
Aero wheels... are they worth it?
Yes.
That's my opinion.