I chose the Great Wheel as the location for my proposal to my girlfriend on our weekend away in Seattle. We got very lucky in that the weather was relatively nice (for Seattle, in November).
I had originally bought tickets online, hoping that there wouldn't be much of a line & we might get our own gondola without having to pay a fortune for the VIP upgrade but that didn't work out so well.
I had contacted the Great Wheel months prior to the weekend to ask their thoughts on the best way to go about this proposal, and the email I got back initially was quite helpful in some ways. However, the person they told me to contact with further questions wasn't overly helpful so it was pretty much a wash in the customer service department.
When we arrived there was a line so I ended up having to stand in the ticket line to upgrade our tickets to the VIP package (it was a calculated risk on my part, no fault of theirs). I had no choice but to get the upgrade, as I wanted to be alone with her when I asked the question & they can't/won't guarantee you your own gondola no matter the situation, without you paying for the upgrade (unless there's no line, and even at that they won't guarantee it).
The VIP upgrade ended up costing us an extra $85 (on top of the normal two ticket prices), and in my opinion was completely not worth it on it's own merits. The upgrade buys you a pass to the front of the line (on our day this would have only been 20-30 min wait), they give you some folding chairs to sit on while you wait (a nice touch, but it's a bit awkward sitting in front of the line full of people if you aren't fond of attention), T-shirts, and then the black gondola with the clear floor. I admit the gondola was probably substantially more comfortable than the normal ones, as it had leather covered bucket seats compared to the normal bench seats, but I don't think any of that justifies the crazy expense for such a short ride. Had I not wanted it to be someplace memorable yet where we could be alone, I would never have bought the upgrade for what amounted to about a 10 minute ride. We enjoyed our time on the wheel, however brief it was (we went around once to load everyone, once without stopping & once to unload everyone, it was quick), and the view was fantastic. I have to dock a few points for the hit & miss customer service (the people loading the ride were great, the lady in the ticket booth was a bit surly, and then the contact with their customer service team I mentioned earlier), and for the lack of value for the VIP upgrade but discounting that this would be a fun way to spend an hour or two once in your life. My only two bits of advice are don't expect much help from them in planning any special events & don't waste your money on the upgrade unless you really want to be alone.