I bought this dolly so I could fit both our cars and my H-D Heritage Softail Classic in our standard size two car garage.
The dolly allows me to have the bike upright and put it right up against the wall--it does the trick and leaves plenty of room for our cars.
Here are some cons (or at least things that you may want to know before you purchase one). My bike is heavy (750 lbs) and the dolly doesn't scoot around the floor quite as easily as it does in the DropTail demo video (shown on the DropTail website). As with almost every heavy item on casters, you have to make sure the wheels are turned in the right direction before you can move it easily. That translates to me moving around to different parts of the dolly to give it a nudge to turn the wheels in the right direction before I scoot it back into the corner of the garage.
Also, it isn't very easy to get the bike out of the wheel chock. Again, the video on the DropTail website shows someone easily getting their bike off the wheel chock that is mounted on a trailer. The difference between the wheel chock on a trailer and a dolly is that the rider can put their feet at "wheel level" on the trailer, whereas the rider is elevated several inches from the ground on the dolly. At 5' 10'', when I put my feet on the ground while sitting on the bike on the dolley, my legs are almost straight. That means less force to pull the bike off the chock. After yanking on the handlebars several times, I put our car ramps under my feet and was able to pull it out.
If you don't have a heavy bike, you may not have these problems, but if you do, you should be aware.
Also, it helps to have the wheel chock adjusted so it is tight against the wheel, much easier getting the bike out.
All in all, I consider the dolly a good investment, it does what I wanted it to do, just need to keep the back muscles strong.