Ok, I admit I didn't read this whole thread. But my choice is definitely the Grom over the Ruckus big time. First of all, I weigh 260 pounds, and the weight limit on a Ruckus is like 220. Second, I have owned 2 50cc scooters, a 2005 Yamaha Zuma (that one was actually fun) and a 2007 Honda Metropolitan. Both these scooters have a sufficient weight rating to support my weight. But both were dangerously slow in town. Most of the streets in my area have a 45 mph speed limit, and traffic goes above 50. You are going to get killed riding a 50cc scooter in town. Especially with the aggressive drivers around here. It's not fun having a jerk in a lifter crew cab truck 2 feet off your ass. I wound up putting most of the mileage on these scooters riding on the shoulders of rural roads, where bicyclists ride. Even a GY6 powered Ruckus (which really isn't a Ruckus anymore) tops out slower than a Grom, and that is on a flat level road. Just try climbing a mountain on it. This is where the Grom really shines. It has real gears and a real clutch. It will go anywhere. It might be slow, but it will get you there. I plan to ride mine to the top of Pikes Peak. Anybody interested in going with me on a Ruckus, including a GY6 Ruckus, just let me know. no way will a CVT Ruckus keep up
This is WAY off topic, I hope it doesn't get me banned. But I own a '93 S10, and belong to an S10 forum. My S10 is set up for drag racing, with a carbureted 383 small block, and tons of other drive train and suspension modifications. I have just over $10,000 into it, not counting the truck, which I bought new back in '93. Fastest time ever was a 10:19. I am a mechanic and did all my own work, other than some machining. There are a lot of other members on that forum that have that much or more into their trucks. But they went a completely different route. They notched the frames, installed air bags, put on huge diameter rims with rubber bands for tires, a high powered stereo, crazy paint job, and are able to lower their trucks all the way to the ground. They are basically for show only.
That's how I see the difference between a Grom and a Ruckus. The Grom is for riding, and can be customized to go faster if that is your thing. The Ruckus is mostly for building show bikes out of. There are guys on Total Ruckus that have $10,000 into their Ruckus. But they are (barely) rolling pieces of are, not practical bikes, or performance bikes. I never cared much for show vehicles (other than vintage cars and bikes) I want something I can ride or drive. Just look at all those virtually unrideable choppers with Harley clone engines that cost a fortune when new. Rolling sculptures, very little else, You can buy a nearly new one on Craigslist now for $10,000. I wouldn't buy one at any price unless I thought I could make money on it. I don't want something to just sit and look at.
So for me, the Grom easily wins out over the Ruckus. It's 25 mph faster right out of the box, will carry more weight, is built stronger, and has real gears, not a CVT. And it can be customized as far as you want to go if that is what you want. I just wanted a nice little bike to cruise around on non freeway roads, and having had two 125cc scooters, decided the Grom was the best way to go. I have not been disappointed.