I took TINIBNZ to the car wash a while ago- The wash rack guys got out their cel phones to get pictures- it was the first one they'd seen. I wash my car at home as well but the wash guys have those giant vacuum cleaners and do a really great job on the windows.
I never take a vehicle thru the spinning wire carwashes. That's just more abuse than I can take. Have been thru a couple "touchless" ones, but it's too short and the back doesn't get very clean. Have not tried the more gentle "wipe" systems. Sorry I don't know what any of the technologies are called.
Driveway washing is always best ... for any vehicle. But I suggest spending a little extra and not using dish washing liquid. I have read on many other sites that it's not good for paint. Even paint with clear-coat. One can get a huge bottle of auto wash at the nearest Pep Boys for a modest few bucks. And you don't need much to wash the little one.
With 3 Smarties and 3 Mercedes, it's tough for me to spend the time in the driveway for a real good car wash. So, I use the local car wash at least once a week per car; wife's more often with the summer bugs. Never had a problem with the car washes. However, it is important to find a car wash that is as gentle as possible - touchles is preferred, if the car is not too dirty.
The thing I do get anal about is when the post-wash dryer guys - with the rags - wipe the wheels THEN use the same rag on the body. HUGE no-no!!! Have 'em chnage the rags often and wipe from the top down.
Also, I have them polish and wax my Mercedes' twice a year; in spring and fall. I will follow the same routine for the Smart cars, as well.
From a green standpoint, especially those of us who live in semi-desert areas with water rationing in place [SoCal], the car wash is more water efficient than your driveway. Most carwashes recycle and filter their water and reuse it multiple times.
I completely agree with the other posters though...brushless is best, make sure they wipe down your smart correctly - top-body-wheels-then clean rags for the dash and console- and finally windows. Besides, my local car wash gives me a discount for my smart!
I live in a very urban part of wintery Chicago, so unfortunately I can't wash mine by hand. I've found the touchless automatic preferrable, except that the sensors don't pick up on the back of the car. The washers continue to spray 5 feet past the car, and then turn. The back of it just ends up kind of grimey looking if you don't bring a towel.
I accidently brought the car twice to ones with the spinning and hanging mops that seem to slap the car around. It was a little freightening at first, but it actually did a great job. I'm not sure if I feel comfortable to go back to one like that. It did feel a little abusive to the car as Roger stated in his post.
Also, I've brought it to a manual wash and it was very easy since the car is so small. The bad thing is that I haven't found an easy way to dry the car. Unfortunately, today it snowed again so my car is back to looking like a disaster. I haven't had any leakage or damage to the car.
I wash my BMW by hand and baby it all the time, but the Smart's a daily driver and will just get the drive-thru washes. There's a video on Youtube of a Fifth Gear car wash comparison and the drive thru actually did the least damage, compared to a handwash a shop and pressure wash by the owner.
I would second the "green" comment. Part of the reason for owning a smart is to use less resources (although the main reason for me is that it is so much fun to drive).
I have taken my smart through a drive-through carwash (brushless) and it didn't clean the back at all. The drive through (manned) carwash was fine, but is expensive. The home wash uses more precious drinking water (and in the Winter you end up with an ice skating rink around it).
I always take my cars to the DIY pressure wash to take of the mag chloride we get here in Colorado. YMMV, t.